Circulatory System  Cardiovascular System = Heart, blood vessels, and blood -Transports H2O, nutrients, waste, O2, CO2, hormones, and immune cells. -Regulates heat, pH, and.

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Transcript Circulatory System  Cardiovascular System = Heart, blood vessels, and blood -Transports H2O, nutrients, waste, O2, CO2, hormones, and immune cells. -Regulates heat, pH, and.

Slide 1

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 2

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 3

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 4

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 5

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 6

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 7

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 8

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 9

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 10

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 11

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 12

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 13

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 14

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 15

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 16

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 17

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 18

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 19

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 20

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 21

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 22

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 23

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 24

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 25

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 26

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 27

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 28

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 29

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 30

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 31

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 32

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 33

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 34

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 35

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 36

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 37

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 38

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 39

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 40

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 41

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 42

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 43

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 44

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 45

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 46

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 47

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 48

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 49

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 50

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 51

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 52

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 53

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 54

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 55

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 56

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 57

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 58

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 59

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 60

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 61

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 62

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 63

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 64

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 65

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 66

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 67

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 68

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 69

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 70

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 71

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 72

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 73

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 74

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 75

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 76

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 77

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 78

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 79

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 80

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 81

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 82

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 83

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 84

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 85

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 86

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 87

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 88

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 89

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 90

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 91

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 92

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 93

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 94

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 95

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 96

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 97

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 98

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 99

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 100

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 101

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 102

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 103

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 104

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 105

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 106

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 107

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 108

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 109

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 110

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 111

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 112

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 113

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 114

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 115

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 116

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 117

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 118

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 119

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 120

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 121

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 122

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 123

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 124

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 125

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 126

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 127

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 128

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 129

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 130

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 131

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 132

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 133

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 134

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 135

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 136

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 137

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 138

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 139

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm


Slide 140

Circulatory System

 Cardiovascular System = Heart,
blood vessels, and blood
-Transports H2O, nutrients, waste, O2,
CO2, hormones, and immune cells.
-Regulates heat, pH, and pressure.
-Associated with lymphatic system.
 Lymphatic System = Lymphatic
vessels, lymphatic hearts, & lymph

Human Cardiovascular

Vascular Terms

 Anastamosis = intercommunication
between separate vessels (net like).
 Portal System = vessels that carry
blood from capillaries to capillaries.
 Sinus = region for “pooling” of fluids.
 Aortic arch = arterial arches that
extend from ventral to dorsal between
pharyngeal openings.
Gnathostomes have 6 early in devel.

Vascular

 Arteries = Large; carry blood away
from heart
 Arterioles = Smaller; carry blood away
from heart
 Capillaries = Very small; gas & nutrient
exchange occur here
 Veinules = Smaller; carry blood to
heart
 Veins = Large; carry blood to heart

Vertebrate Blood

 Blood = connective tissue; cells (in
vertebrates) in a water-based matrix.
 Plasma = matrix around blood cells.
Transports: H2O, nutrients, waste,
CO2, hormones
 Erythrocytes = Contain hemoglobin;
transport O2; No nuclei in mammals.
 Leucocytes = Immune cells.
 Platelets = Cell fragments, involved in
clotting after damage.

Vertebrate Blood

Plasma

Hematopoesis – Blood Devel.

 Hematopoesis = blood development.
 Blood islands form in splanchnic
mesoderm in yolk sac = 1st site of
hematopoesis (always nucleate cells).
Early fetal human red blood cells have
nuclei.
 Additional stem cells in splanchnic
mesoderm around heart migrate to
hematopoetic areas (spleen, kidneys, liver, &

Vascular Development

 Mostly from splanchnic mesoderm.
 Angiogenesis = blood vessel
formation
 Blood islands in yolk sac merge to form
vessels that then extend into rest of
embryo.
Cardiovascular system starts in yolk
sac and spreads to rest of embryo.

Human Blood Islands

Basic Chordate Arterial Circ.

 Blood moves from posterior and

ventral to the pharynx (heart/sinus
venosus)
 Anteriorly under the pharynx (ventral
aorta)
 Dorsolaterally up through the
pharynx (pharyngeal/aortic arches)
 Then to the body anteriorly and
posteriorly from the dorsal pharynx
(dorsal aorta).

Lancelet Arterial Circulation
dorsal aorta (paired - median)

sinus venosus (median)
ventral aorta (median)

Lancelet Venous Circulation
Anterior & posterior cardinal veins (paired)

sinus venosus (median)
hepatic vein (median)

Lancelet Circulation

ventral
aorta

dorsal
aorta

s.v.
dorsal
aorta

common
cardinal
vein

anterior
cardinal
vein

s.v.
hepatic
vein

posterior
cardinal
vein

Basic Amniote Circulation

Early Human Embryo Arterial
left & right
dorsal aortas

aortic
arch II
aortic
arch I
ventral aorta

III

IV

umbilical
artery

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
artery

Early Human Embryo Arterial
left & right
dorsal aortas

IV VI
III

ventral aorta

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial
descending aorta

carotids

ventral aorta

IV VI pulmonary
III

umbilical
artery

heart

(truncus arteriosus)

vitelline
artery

Early Human Embryo Arterial

Embryonic Arteries
ventral aorta

dorsal aorta

I
II

III
IV
VI
HEART

I II III IV V VI

V

Human Embryonic Arteries
external carotid
internal carotid
common carotid

I
II

III
IV

subclavian

aortic arch

VI

pulmonary artery
HEART

ductus arteriosus
(before birth)

descending aorta

Human Embryonic Arteries

Human Aortic Arches

Human Fetal Circulation
Upper Left
Arch VI

Early Human Embryo Circulation
left & right anterior
cardinal veins

left & right posterior
cardinal veins

left & right
common
cardinal
veins
ventral aorta

heart

(truncus arteriosus) sinus venosus
atrium
ventricle
bulbis cordis

vitelline
(hepatic)
veins

allantoic
(umbilical) veins

Early Human Embryo Circulation
superior
left & right anterior
vena
cardinal veins
cava

left & right posterior
cardinal veins

azygous vein
jugular
veins

inferior
vena
cava
hepatic
portal
hepatic vein
vitelline
vein
(hepatic)
veins

heart

allantoic
(umbilical) veins

Human Anterior Venous
Development

Basic Vertebrate Circulation

Blood Vessel Structure

 Endothelium = simple squamous
epithelium lining inside of blood
vessels (tunica intima)
 Tunica externa = fibrous connective
tissue surrounding the outside of the
vessel
 Tunica media = between the tunica
intima and tunica externa; elastic
connective tissue and/or smooth
muscle.

Vessel Structure

 Arteries = Large; carry blood away
from heart;
thick tunica media composed
primarily of smooth muscle;
accommodate high blood pressure
 Capillaries = Very small; gas &
nutrient exchange occur here;
lack tunica media and tunica externa

Vessel Structure

 Veins = Vessels that carry blood to
the heart; thin tunica media made
primarily of connective tissue
one-way valves promote the return
of blood under low pressure

Vertebrate Vessels
vein

tunica intima
(endothelium)

capillary

artery

Adult Human Arterial system

Adult Human Arterial system
external carotid
internal carotid
common carotid
vertebral
aorta*
coeliac*
superior mesenteric*
renal
gonadal
inferior mesenteric*

subclavian
axillary
humeral circumflex
internal thoracic
lateral thoracic
brachial
deep brachial
radial
ulnar
common iliac
external iliac
internal iliac
femoral circumflex
deep femoral
femoral
popliteal
anterior tibial
posterior tibial

Pulse Points

Carotid & Radial Pulse Points

Human Venous System

Azygous vein

Human Venous System

Human Arm Venous System

Human Leg Venous System

Human Varicose veins

Hematopoesis

 In non-amniotes occurs primarily in
the spleen, kidneys, and liver.
Especially the spleen.
 Hagfishes, lampreys, & lungfishes =
no spleen
 In amniotes occurs in bone marrow
(especially in humans and other
mammals) as well as in other tissues.
No bone marrow in birds.

spleen
lost

Subphylum Vertebrata

*
hematopoesis in
marrow

discrete spleen
blood cells

*erythrocytes lack nuclei

Lancelet Circulation

Vertebrate Circulation
dorsal
aorta

ventral
aorta
subclavian
external
heart artery
carotid

Iliac
artery

Vertebrate Circulation
anterior & posterior
cardinal veins
jugulars

heart

renal portal

hepatic
portal

lateral
subclavian abdominal iliac
vein
vein
vein

Aortic Arches

 Gnathostomes = Arch I lost in adults; 6
arches early in development
 Sarcopterygiians = Pulmonary arteries
from arch VI
 Tetrapods & Actinopts. = Arch II lost
 Amniotes = Arch V lost
 Mammals = left Arch IV forms aorta;
right Arch IV forms base of subclavian
 Birds = right Arch IV forms aorta

Gnathostome Embryo Aortic Arches
external
carotid

internal
carotid

I
II

III
IV
V

ventral
aorta

VI
I II III IV V VI

heart

dorsal
aorta

dorsal
aorta

Chondrichthyan Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Teleost Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

Lungfish Aortic Arches
I
II

III
IV
V
VI
I II III IV V VI

heart

pulmonary
artery

Amphibian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lizard Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Bird Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Lepidosaur Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

Mammalian Aortic Arches
external
carotid

internal
carotid

I
II
III
IV
V
VI
I II III

IV V VI

heart

pulmonary
artery

arch II lost

Subphylum Vertebrata

arch V
lost
arch II
lost

arch VI
forms pulmonary
connection

arch I
lost;
6 arches form in development

Amniota

left arch IV
forms aorta; right
arch IV forms
right subclavian

right arch
IV forms
aorta

Gnathostome Adult Aortic Arches
Aortic Arch

Chondrichthys

Actinopterygii

lungfishes

I
II

lost
gill arch

lost
lost

lost
gill arch

III

gill arch

gill arch

gill arch

IV

gill arch

gill arch

gill arch

V

gill arch

gill arch

gill arch

VI

gill arch

gill arch

arch
& pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

amphibians

turtles

lizards

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids
l. and r. aortic
arches
aortic arch

common
carotids
l. and r. aortic
arches
lost

common
carotids
l. and r. aortic
arches
lost

pulmonary
artery

pulmonary
artery

IV
V

(lost in frogs)

VI

aortic arch &
pulmonary
artery

Gnathostome Adult Aortic Arches
Aortic Arch

crocodilians

birds

Mammalia

I
II

lost
lost

lost
lost

lost
lost

III

common
carotids

com. carotids /
subclavian
bases

common
carotids & ext.
carotid base

IV

l. and r. aortic
arches

V

lost

l. lost
r. aorta
lost

l. aorta
r. subclavian
lost

VI

pulmonary
artery

pulmonary
artery

pulmonary
artery

Venous System

 Gnathostomes = renal portal vein
 Tetrapods = inferior vena cava from
right hepatic; anterior cardinal veins
form internal & external jugular veins
 Mammals = inferior vena cava
connects to & replaces renal portal
 Some Mammals (humans, cats, etc.) =
lose the left anterior cardinal vein (the
right anterior cardinal vein = superior vena
cava)

Venous System
sinus
venosus
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal

posterior
cardinal

Shark Venous System
internal
jugular
subclavian
hepatic
vein
hepatic
portal

anterior
cardinal
common
cardinal
posterior
cardinal

renal
portal

Amphibian Venous System
external
jugular
subclavian
hepatic
vein
hepatic
portal

internal
jugular

anterior
cardinal
common
cardinal
posterior
cardinal
posterior
vena cava
renal
portal

iliac

Reptile Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
portal

iliac

Mammal Venous System
external
jugular
subclavian

internal
jugular
anterior
cardinal

hepatic
vein
hepatic
portal

posterior
vena cava
renal
vein

iliac

Gnathostome Venous System
Veins

Chondrichthys

Actinopterygii

lungfishes

ant. card.
com. card.

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

ant. cardinal
com. cardinal

post. card.

post. cardinal

post. cardinal

hep. portal

hepatic portal

hepatic portal

hepatic portal

renal port.

renal portal

renal portal

renal portal

hepatic

post. cardinal
(rt. = posterior
“vena cava”)
2 hepatic veins 2 hepatic veins 2 hepatic veins

Gnathostome Venous System
Veins
ant. card.

amphibians

turtles

Lepidosauria

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)

com. card.

com. cardinal
(s. vena cavas)

com. cardinal com. cardinal
(s. vena cavas)
(s. vena cavas)
post. card. post. cardinal
l. lost
l. lost
r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. p. vena cava r. p. vena cava r. p. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

renal portal

Gnathostome Venous System
Veins

crocodilians

birds

Mammalia

ant. card.

ant. cardinal
ant. cardinal
ant. cardinal
(jugular vein & (jugular vein & (jugular vein &
brachiocephalics) brachiocephalics) brachiocephalics)
com. card. com. cardinal com. cardinal com. cardinal
(s. vena cavas
(s. vena cavas)
(s. vena cavas)
-left s. v. c. lost in some)

post. card.

l. lost
l. lost
l. lost
r. azygous vein r. azygous vein r. azygous vein
hepatic
l. hepatic vein l. hepatic vein l. hepatic vein
r. i. vena cava r. i. vena cava r. i. vena cava
hep. portal hepatic portal hepatic portal hepatic portal
renal port.

renal portal

renal portal

lost

Hepatic Portal Vein

 Vein from yolk sac to heart (vitelline vein)
impinged on by hepatic diverticulum and
forms hepatic capillaries.
gut
liver (with hepatic veins)
heart
hepatic portal vein
vitelline vein
(from yolk sac)

Subphylum Vertebrata

*
jugular veins;
rt. hepatic =
posterior
vena cava
renal portal; subclavians
*renal portal lost

Heart

 Heart = Muscular pump, moves blood
via rhythmic contraction.
 Contraction involuntary & initiated within
the heart. (not-neuronal)
Modified branching (cardiac) muscle
cells transmit contraction signal.
 Chamber = Cavity for blood collection
separated by valves
 Valves = Flaps of tissue that prevent
back-flow of fluid (in this case blood)

Human Heart Development

 Formed from splanchnic mesoderm.
 Endocardial tissue = forms simple

squamous epithelium that lines the heart
chambers and forms the heart valves
 Myocardial = epithelium forms heart muscle
 Hollow endocardial primordia form by
splanchnic mesoderm ingression, then fuse to
form a the endocardium (endothelium).
 Epithelial splanchnic mesoderm surrounds
the endocardium forming the cardiac muscle
of the myocardium.

Human Heart Development

endocardium
myocardium

Human Heart Development

(ventral aorta)

Sinus Venosus

Heart Chambers & Valves

 Sinus venosus = slightly muscular chamber;
receives blood from cardinal veins = sinoatrial node
(“pacemaker”) in amniotes.

 Sinoatrial valve = between s.v. & atrium.
 Atrium = slightly muscular chamber.
 Atrioventricular valve = between atrium &
ventricle.

 Ventricle = highly muscular chamber.
 Conus arteriosus/ Bulbus arteriosus =
chamber after ventricle (muscular with valves
= conus; elastic, no valves = bulbus ;
embryonic = bulbis cordis)

Human Heart Development

Human Heart Development

 Sinus Venosus lost except some cells
that become the sinoatrial node
(“pacemaker”)
 Sinoatrial valve lost.
 Atrium divides into right and left.
 Atrioventricular valve divides to form
(right) tricuspid and (left) bicuspid/mitral
valves
 Ventricle divides into right and left.

Human Heart Development

 Bulbis cordis lost.
 Ventral aorta (truncus arteriosus)

divides to become
- (left) ascending aorta that will
maintain connection to aortic arches III
& IV and
- (right) pulmonary trunk artery that
will maintain connection to aortic arch
VI.

Human Heart Blood Flow

Human Heart Blood Flow

Heart Chambers & Valves

Heart Position/Stethoscope

Blood Flow From Heart
high oxygen

low oxygen

Heart Chambers & Valves

Teleost

Heart Chambers

 Sarcopterygiians = at least partially
developed interatrial septum
 Tetrapods = complete interatrial
septum
 Amniotes = conus arteriosus lost
during devel; sinus venosus incorp.
into right atrium; at least partially
developed interventricular septum
 Mammals & Archosaurs = complete
interventricular septum

Heart Chambers & Valves

Heart Chambers & Valves

bulbus
arteriosus

Subphylum Vertebrata

complete
interatrial
septum
partial interatrial
septum

heart (sinus venosus, atrium, ventricle,
conus arteriosus)

Amniota

complete
complete
interventricular
interventricular
septum
septum
conus arteriosus lost in adult;
incomplete interventricular septum;
sinus venosus lost (in rt. atrium)

Gnathostome Heart
Chambers

Chondrichthys

Actinopterygii

lungfishes

Sinus
Venosus
Atrium

sinus venosus

sinus venosus

sinus venosus

atrium

atrium

atrium (partially
l.-r. divided)

Ventricle

ventricle

venticle

ventricle

Conus
Arteriosus

conus
arteriosus

bulbus
arteriosus (not

conus
arteriosus

muscular)

Gnathostome Heart
Chambers

amphibians

Sinus
Venosus
Atrium

sinus venosus

Ventricle

ventricle

Conus
Arteriosus

lizards

turtles

sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

conus
arteriosus

left atrium
right atrium

left atrium
right atrium

ventricle (partial. ventricle (partial.
left-right divided)

left-right divided)

lost

lost

Gnathostome Heart
Chambers
Sinus
Venosus
Atrium
Ventricle

crocodilians

birds

Mammalia

sinoatrial node sinoatrial node sinoatrial node
(incorp. in rt. atrium) (incorp. in rt. atrium) (incorp. in rt. atrium)

left atrium
right atrium

left atrium
right atrium

left atrium
right atrium

left ventricle
right ventricle

left ventricle
right ventricle

left ventricle
right ventricle

lost

lost

(connected by
foramen of Panizza)

Conus
Arteriosus

lost

Lymphatic System

 Plasma in capillaries is forced into the
tissues by blood pressure.
 Edema = swelling of tissues due to
accumulation of fluid (plasma/lymph).
 Usually, edema is avoided because…
plasma in tissues diffuses into blind
lymphatic capillaries and is called
lymph.

Lymphatic System
artery

capillaries

vein

Lymphatic System

 Lymphangitis = inflamation of a lymph
vessel. (ROOT WORDS)
Lymphangitis of the vessel indicated by
the arrow caused the edema in the
middle finger.

Lymphatic System

 Lymph vessels = thin walled vessels
with valves (similar in structure to veins,
but with weak contractile ability); return
lymph to venous system.
 Lymph nodes (lymphatic cisterns) =
expanded lymph vessels filled with
connective tissue and leukocytes.
Immunological filters.
 Lacteals = lymph vessels in villi of the
jejuno-ileum (small intestine) absorb fats.

Lymph Vessel

Lymph Node & Lg. Vessel
(in mesentary proper)

Human Cephalic Lymph System

Human Lymphatic System

Lymphatic System

 Contractile lymph vessels exist in most
vertebrates (Form localized Lymph Hearts in
hagfishes, lungfishes, amphibians, turtles, liz.
& snakes, & ostriches+related birds)

 Lacteals = lymph vessels in the intestinal
villi – Only in TETRAPODS.
 Lymph nodes / sacs / cisterns =
expanded lymph vessels filled with
connective tissue and leukocytes. Only in
AMNIOTES.

Human Lymphatic System

Subphylum Vertebrata

lymph
nodes &
cisterns
lacteals

General Respiratory Systems

 Ventilation = movement of air or water
across a respiratory surface.
 Apnea = cessation of ventilation
 Unidirectional ventilation = air/water
moves 1 direction over resp. surface
 Bidirectional ventilation = air/water
moves 2 directions over resp. surface.
(tidal)
 Concurrent & Counter current
exchange

Concurrent
Same Direction Current

water or air

blood

from body (heart)

to body

Counter Current
Counter Current System

water or air
blood

to body

from body (heart)

Human Trachea & Lung
Development

Human Respiratory System

in
lung

nasal cavity
pharynx
larynx
trachea
bronchus
bronchiole
alveolus

Human Respiratory System

Human Larynx

Human Lungs

Human Ventilation

Aquatic Respiratory Structures

 Skin is a significant respiratory surface
in many NON-amniotes.
 Gills = aquatic pharyngeal respiratory
surfaces. (Internal = within pharynx;
External = protrude from pharynx)
salamander (axolotl)

reedfish

lungfish

Internal Gills
Chondrichthys

Actinopterygii

Gills

 Gill = bony pharyngeal arch and two sets
of filaments.
 Absent in Amniotes and adult
Lissamphibians
 Each filament bears many lamellae
(small, flat projections) & blood passes
through capillaries in the lamellae.
 Blood movement through lamellae sets
up a counter current system.

Gills

Counter Current

Gill Filament
afferent
lamella

efferent

Lungs/Swimbladders

 Lung(s) = aerial gut diverticulum

respiratory surface. (Osteichthys)
In fishes called swimbladder & usually
used for buoyancy as well.
 Pneumatic duct = Connection to
digestive tract in Actinopterygii & Dipnoi.
Trachea (in Tetrapods) is a pneumatic
duct held open with cartilage rings.

Lungs/Swimbladders

 Respiratory lungs/swimbladders are
often compartmentalized.
 Faveoli = non-mammal lung chambers.
 Alveoli = rounded mammal lung
chambers.

Lungs/Swimbladders (Osteichthys)

 Ancestral lungs/swimbladders:

Ventral trachea/pneumatic duct.
Two “lungs”
 Swimbladder of non-reedfish
actinopterygiians:
Dorsal pneumatic duct.
One lung dorsal to esophagus.
(Pneumatic duct lost in some teleosts.)

Lungs/Swimbladders

Amia calva

lungfish

Polypterus
carp

salamander
bass

Craniate Respiration

alveoli

gill
filaments
lost

lungs

trachea

(swimbladder)

(with
cartilage
“rings”)

respiratory gills with filaments

Class Actinopterygii

single dorsal lung with
dorsal connection to
digestive tract

Aerial Respiratory Modifications

 Ancestrally - amphibians & “fishes”
- “Swallow” air – push into lungs
- Elastic lungs recoil to push air out.
 Prehepatic diaphragm (mammals)
- Negative pressure pulls air into lungs
- Body cavity contraction pushes air out.
 Posthepatic diaphragm (crocodilians)
- Negative pressure pulls air into lungs
- Liver pushes air out of lungs.

“swallow” air

Ventilation
prehepatic

posthepatic

Bird Respiration

 Parabronchi (birds) = one-way,
passageways through the lung faveoli.
 Lungs not very compressible.
 Air Sacs (birds) = membranous sacs
for containing air (9 off of each lung)
 Air moved by expansion & contraction
of air sacs.
 Countercurrent, constant flow of O2 rich
air over capillaries even when exhaling.

Avian Lungs

Avian Inhalation

Avian Exhalation

Avian Respiration

Amniota

*

prehepatic
diaphragm

air sacs;
parabronchi

* posthepatic diaphragm