Transcript Nerve activates contraction

Blood
•The only fluid tissue in the human body
•Classified as a connective tissue
•Components of blood
•Living cells
•Formed elements
•Non-living matrix
•Plasma
Blood
•If blood is centrifuged
•Erythrocytes sink to the bottom (45 percent
of blood, a percentage known as the
hematocrit)
•Buffy coat contains leukocytes and platelets
(less than 1 percent of blood)
•Buffy coat is a thin, whitish layer between
the erythrocytes and plasma
•Plasma rises to the top (55 percent of blood)
Figure 10.1 (1 of 2)
Figure 10.1 (2 of 2)
Physical Characteristics of Blood
•Color range
•Oxygen-rich blood is scarlet red
•Oxygen-poor blood is dull red(cyanosis)
•pH must remain between 7.35–7.45
•Blood temperature is slightly higher than body
temperature at 100.4°F
•In a healthy man, blood volume is about 5–6
liters or about 6 quarts
•Blood makes up 8 percent of body weight
Blood Plasma
•Acidosis
•Blood becomes too acidic
•Alkalosis
•Blood becomes too basic
•In each scenario, the(buffer systems)
respiratory system(H2co3) and
kidneys(amonia) help restore blood pH to
normal
Formed Elements
•Erythrocytes
•Red blood cells (RBCs)
•Leukocytes
•White blood cells (WBCs)
•Platelets(Thrombocytes)
•Cell fragments
Formed Elements
•Erythrocytes (red blood cells or RBCs)
•Main function is to carry oxygen
•Anatomy of circulating erythrocytes
•Biconcave disks
•Essentially bags of hemoglobin
•Anucleate (no nucleus)
•Contain very few organelles
•5 million RBCs per cubic millimeter of blood
Lymphocyte
Erythrocytes
Platelets
Neutrophils
Figure 10.2
Formed Elements
•Hemoglobin
•Iron-containing protein
•Binds strongly, but reversibly, to oxygen
•Each hemoglobin molecule has four oxygen
binding sites
•Each erythrocyte has 250 million
hemoglobin molecules
•Normal blood contains 12–18 g of
hemoglobin per 100 mL blood, less than10g
is anaemia
Formed Elements
•Homeostatic imbalance of RBCs
•Anaemia is a decrease in the oxygencarrying ability of the blood& not decrease #
of RBC
•Iron deficiency anaemia
•Sickle cell anaemia (SCA) results from
abnormally shaped heamoglobine, comes in
crisis in young black children on eating fava
beans
•Polycythemia is an excessive or abnormal
increase in the number of erythrocytes
Figure 10.3
Formed Elements
•Polcythemia
•Disorder resulting from excessive or
abnormal increase of RBC
•May be caused by bone marrow cancer
(polycythemia vera)
•May be a response to life at higher
altitudes (secondary polycythemia)
•Increased RBC slows blood flow and
increases blood viscosity ,lead to
thrombosis
Formed Elements
•Leukocytes (white blood cells or WBCs)
•Crucial in the body’s defense against disease
•These are complete cells, with a nucleus and
organelles(segmented nucleus)
•Able to move into and out of blood vessels
(diapedesis)
•Can move by ameboid motion
•Can respond to chemicals released by damaged
tissues
•5, 000 to 11,000 WBC per cubic millimeter of
blood
Formed Elements
•Abnormal numbers of leukocytes
•Leukocytosis
•WBC count above 11,000 leukocytes/mm3
•Generally indicates an infection
•Leukopenia
•Abnormally low leukocyte level
•Commonly caused by certain drugs such as
corticosteroids and anticancer agents
•Leukemia
•Bone marrow becomes cancerous, turns out
excess WBC, over 200,000, immature WBC,s
Formed Elements
•Types of leukocytes
•Granulocytes
•Granules in their cytoplasm can be stained
•Possess lobed nuclei
•Include neutrophils, eosinophils, and
basophils
•Agranulocytes
•Lack visible cytoplasmic granules
•Nuclei are spherical, oval, or kidney-shaped
•Include lymphocytes and monocytes
Formed Elements
•List of the WBCs from
most to least
abundant
•Neutrophils
•Lymphocytes
•Monocytes
•Eosinophils
•Basophils
•Easy way to
remember this list
•Never
•Let
•Monkeys
•Eat
•Bananas
Figure 10.4
Formed Elements
•Types of granulocytes
•Neutrophils
•Cytoplasm stains pale pink and contains fine
granules
•Deep purple nucleus contains three to seven
lobes
•Function : phagocytosis at active sites of
infection
•Numbers increase during acute infections
•3,000–7,000 neutrophils in a cubic millimeter
of blood (40–70% of WBCs)
Formed Elements
•Types of granulocytes (continued)
•Eosinophils
•Red, coarse cytoplasmic granules
•Figure-8 or bilobed nucleus stains bluered
•Function to kill parasitic worms and play a
role in allergy attacks
•100–400 eosinophils in a cubic millimeter
of blood (1–4% of WBCs)
Formed Elements
•Types of granulocytes (continued)
•Basophils
•Sparse but large blue-purple granules
•U- or S-shaped nucleus stains dark blue
•Release histamine (vasodilator) at sites of
inflammation, increasd in allergic
conditions
•Contain heparin (anticoagulant)
•20–50 basophils in a cubic millimeter of
blood (0–1% of WBCs)
Formed Elements
•Types of agranulocytes
•Lymphocytes
•Cytoplasm is pale blue
•Dark purple-blue nucleus
•Functions as part of the immune response
• B lymphocytes produce antibodies
• T lymphocytes are involved in graft
rejection, fighting tumors and viruses
•1,500–3,000 lymphocytes in a cubic
millimeter of blood (20–45% of WBCs)
Formed Elements
•Types of agranulocytes (continued)
•Monocytes
•Largest of the white blood cells
•Gray-blue cytoplasm
•Dark blue-purple nucleus is often kidney
shaped
•Function as macrophages
•Important in fighting chronic infection
•100–700 monocytes per cubic millimeter
of blood (4–8% of WBCs)
Formed Elements
•Platelets
•Needed for the clotting process, by
activating 12 clotting factors contained
inside
•Platelet count ranges from 150,000 to
400,000 per cubic millimeter of blood
•300,000 is considered a normal number of
platelets per cubic millimeter of blood
Hematopoiesis
•Blood cell formation
•Occurs in red bone marrow
•All blood cells are derived from a common
stem cell (hemocytoblast)
•Hemocytoblast differentiation
•Lymphoid stem cell produces lymphocytes
•Myeloid stem cell produces all other formed
elements
Figure 10.4
Formation of Erythrocytes
•Unable to divide, grow, or synthesize proteins
•Wear out in 100 to 120 days
•When worn out, RBCs are eliminated by
phagocytes in the spleen or liver
•Lost cells are replaced by division of
hemocytoblasts in the red bone marrow
Control of Erythrocyte Production
•Rate is controlled by a hormone
(erythropoietin)
•Kidneys produce most erythropoietin as a
response to reduced oxygen levels in the
blood
Formation of White Blood Cells and
Platelets
•Controlled by hormones
•Colony stimulating factors (CSFs) and
interleukins prompt bone marrow to
generate leukocytes
•Thrombopoietin stimulates production of
platelets
Hemostasis
•Stoppage of bleeding resulting from a break in
a blood vessel
•Hemostasis involves three phases
•Vascular spasms
•Platelet plug formation
•Coagulation (blood clotting)
•Clotting time 2-4 minutes
Undesirable Clotting
•Thrombus
•A clot in an unbroken blood vessel
•Can be deadly in areas like the heart &deep
veins of leg
•Embolus
•A thrombus that breaks away and floats
freely in the bloodstream
•Can later clog vessels in critical areas such
as the brain, heart &lung
Bleeding Disorders
•Thrombocytopenia
•Platelet deficiency
•Even minor truma can cause bleeding from
small blood vessels that require platelets for
clotting
•Hemophilia
•Hereditary bleeding disorder
•Normal clotting factors are missing
Blood Groups and Transfusions
•Large losses of blood have serious
consequences
•Loss of 15 to 30 percent causes weakness
•Loss of over 30 percent causes shock,
which can be fatal
•Transfusions are the only way to replace blood
quickly
•Transfused blood must be of the same blood
group
ABO Blood Groups
•The presence of both antigens A and B is
called type AB
•The presence of antigen A is called type A
•The presence of antigen B is called type B
•The lack of both antigens A and B is called
type O
ABO Blood Groups
Blood Group
RBC Antigens
Plasma antibodies
Blood that can be
received
AB
A, B
None
A, B, AB, O
Universal recipient
B
B
Anti-A
B, O
A
A
Anti-B
A, O
O
None
Anti-A, Anti-B
O
Universal donor
Rh Blood Groups
•Named because of the presence or absence
of Rh antigens (agglutinogen D) that was
originally defined in Rhesus monkeys
•Most Americans are Rh+ (Rh positive)
•Problems can occur in mixing Rh+ blood into a
body with Rh– (Rh negative) blood
Rh Dangers During Pregnancy
•Danger occurs only when the mother is Rh–
and the father is Rh+, and the child inherits the
Rh+ factor
•RhoGAM shot can prevent buildup of
anti-Rh+ antibodies in mother’s blood
Rh Dangers During Pregnancy
•The mismatch of an Rh– mother carrying an
Rh+ baby can cause problems for the unborn
child
•The first pregnancy usually proceeds without
problems
•The immune system is sensitized after the
first pregnancy
•In a second pregnancy, the mother’s
immune system produces antibodies to
attack the Rh+ blood (hemolytic disease of
the newborn)
Blood typing can be done by adding anti A
or anti B
•Coagulation or no coagulation leads to
determining blood type
•Typing for ABO and Rh factors is done in the
same manner
•Cross matching—testing for agglutination of
donor RBCs by the recipient’s serum, and vice
versaA
Blood being tested
Serum
Anti-B
Anti-A
Type AB (contains
antigens A and B;
agglutinates with
both sera)
Agglutinated
RBCs
Type B (contains
antigen B;
agglutinates with
anti-B serum)
Type A (contains
antigen A;
agglutinates with
anti-A serum)
Type O (contains
no antigens;
does not
agglutinate with
either serum)
Figure 10.8
The heart & blood vessels
•The heart pumps blood
•Blood vessels allow blood to circulate to all
parts of the body
•The functions of the cardiovascular system
•To deliver oxygen and nutrients to cells and
tissues
•To remove carbon dioxide and other waste
products from cells and tissues
The Heart
•Location
•Thorax between the lungs in the inferior
mediastinum
•Orientation
•Pointed apex directed toward left hip
•Base points toward right shoulder
•About the size of your fist
Midsternal line
2nd rib
Sternum
Diaphragm
Point of
maximal
intensity
(PMI)
(a)
Figure 11.1a
Superior
Superior
vena
cava
vena cava
Pulmonary
Pulmonary
trunk
trunk
Diaphragm
Diaphragm
Aorta
Aorta
Parietal
Parietal
pleura
(cut)
pleura (cut)
Left lung
Left lung
Pericardium
Pericardium
(cut)
(cut)
Apex of
Apex of
heart
heart
(c)
(c)
Figure 11.1c
Brachiocephalic trunk
Left common carotid artery
Superior vena cava
Left subclavian artery
y
Right pulmonary
artery
Aortic arch
Ascending aorta
Ligamentum arteriosum
Left pulmonary artery
Pulmonary trunk
Left pulmonary veins
Right pulmonary
veins
Left atrium
Right atrium
Right coronary artery
in coronary sulcus (right
atrioventricular groove)
Anterior cardiac vein
Auricle of left atrium
Circumflex artery
Left coronary artery in
coronary sulcus (left
atrioventricular groove)
Left ventricle
Right ventricle
Great cardiac vein
Marginal artery
Small cardiac vein
Inferior vena cava
(a)
Anterior interventricular
artery (in anterior
interventricular sulcus)
Apex
Figure 11.3a
The Heart: Coverings
•Pericardium—a double-walled sac
•Fibrous pericardium is loose and superficial
•Serous membrane is deep to the fibrous
pericardium and composed of two layers
•Visceral pericardium
• Next to heart; also known as the
epicardium
•Parietal pericardium
• Outside layer that lines the inner surface
of the fibrous pericardium
•Serous fluid fills the space between the layers
of pericardium
Pulmonary
Pulmonary
trunk
trunk
Pericardium
Myocardium
Fibrous pericardium
Fibrous pericardium
Parietal layer of serous
Parietal layer of serous
pericardium
pericardium
Pericardial
cavity
Pericardial cavity
Epicardium
(visceral layer
of serous
Heart
pericardium) wall
Heart
wall
Myocardium
Endocardium
Heart chamber
Figure 11.2
The Heart: Heart Wall
•Three layers
•Epicardium
•Outside layer
•This layer is the visceral pericardium
•Connective tissue layer
•Myocardium
•Middle layer
•Mostly cardiac muscle
•Endocardium
•Inner layer
•Endothelium
Superior vena cava
Aorta
Left pulmonary artery
Right pulmonary artery
Left atrium
Right atrium
Left pulmonary veins
Right pulmonary
veins
Pulmonary semilunar valve
Fossa ovalis
Right atrioventricular
valve (tricuspid valve)
Left atrioventricular valve
(bicuspid valve)
Aortic semilunar valve
Left ventricle
Right ventricle
Chordae tendineae
Interventricular septum
Inferior vena cava
Myocardium
Visceral pericardium
(b) Frontal section showing interior chambers and valves.
Figure 11.3b
The Heart: Chambers
•Right and left side act as separate pumps
•Four chambers
•Atria
•Receiving chambers
• Right atrium
• Left atrium
•Ventricles
•Discharging chambers
• Right ventricle
• Left ventricle
The Heart: Septa
•Interventricular septum
•Separates the two ventricles
•Interatrial septum
•Separates the two atria
The Heart’s Role in Blood Circulation
•1.Systemic circulation
•Blood flows from the left side of the heart
through the body tissues and back to the
right side of the heart
•2.Pulmonary circulation
•Blood flows from the right side of the heart
to the lungs and back to the left side of the
heart
Capillary beds
of lungs where
gas exchange
occurs
Pulmonary Circuit
Pulmonary
arteries
Pulmonary
veins
Aorta and
branches
Venae
cavae
Left
atrium
Left
ventricle
Right
atrium
Heart
Right
ventricle
Systemic Circuit
KEY:
Oxygen-rich,
CO2-poor blood
Oxygen-poor,
CO2-rich blood
Capillary
beds of all
body tissues
where gas
exchange
occurs
Figure 11.4
The Heart: Valves
•Allow blood to flow in only one direction to
prevent backflow
•Four valves
•Atrioventricular (AV) valves—between atria
and ventricles
•Bicuspid (mitral) valve (left side of heart)
•Tricuspid valve (right side of heart)
•Semilunar valves—between ventricle and
artery
•Pulmonary semilunar valve
•Aortic semilunar valve
The Heart: Valves
•AV valves
•Anchored in place by chordae tendineae
attached to papillary muscles
•Open during heart relaxation and closed
during ventricular contraction
•Semilunar valves
•Closed during heart relaxation but open
during ventricular contraction
•Heart Sounds are due closure of: AV valves,
in first sound & semiular valves in second
sound.
Coronary Circulation
•The heart has its own nourishing circulatory
system consisting of
•Coronary arteries—branch from the aorta to
supply the heart muscle with oxygenated blood
•Cardiac veins—drain the myocardium of blood
•Coronary sinus—a large vein on the posterior
of the heart, receives blood from cardiac veins
& empties into the right atrium .
Brachiocephalic trunk
Left common carotid artery
Superior vena cava
Left subclavian artery
Right pulmonary artery
Aortic arch
Ascending aorta
Ligamentum arteriosum
Left pulmonary artery
Pulmonary trunk
Left pulmonary veins
Right pulmonary
veins
Left atrium
Right atrium
Right coronary artery
in coronary sulcus (right
atrioventricular groove)
Anterior cardiac vein
Auricle of left atrium
Circumflex artery
Left coronary artery in
coronary sulcus (left
atrioventricular groove)
Left ventricle
Right ventricle
Great cardiac vein
Marginal artery
Small cardiac vein
Inferior vena cava
(a)
Anterior interventricular
artery (in anterior
interventricular sulcus)
Apex
Figure 11.3a
The Heart: Associated Great Vessels
•Arteries
•Aorta
•Leaves left ventricle
•Pulmonary arteries
•Leave right ventricle
The Heart: Associated Great Vessels
•Veins
•Superior and inferior venae cavae
•Enter right atrium
•Pulmonary veins (four)
•Enter left atrium
The Heart: Conduction System
•Special tissue sets the pace
•Sinoatrial node = SA node (“pacemaker”), is
in the right atrium
•Atrioventricular node = AV node, is at the
junction of the atria and ventricles
•Atrioventricular bundle = AV bundle (bundle
of His), is in the interventricular septum
•Bundle branches are in the interventricular
septum
•Purkinje fibers spread within the ventricle wall
muscles
Superior
vena cava
Sinoatrial (SA)
node (pacemaker)
Left atrium
Atrioventricular
(AV) node
Right atrium
Atrioventricular
(AV) bundle
(bundle of His)
Bundle branches
Purkinje fibers
Purkinje fibers
Interventricular
septum
Figure 11.7
Heart Contractions
•Once SA node starts the heartbeat
•Impulse spreads to the AV node
•Then the atria contract
•At the AV node, the impulse passes through
the AV bundle, bundle branches, and Purkinje
fibers, then ventricles contract
•Blood is ejected from the ventricles to the
aorta and pulmonary trunk as the ventricles
contract
Heart Contractions
•Homeostatic imbalance
•Heart block—damaged AV node releases
them from control of the SA node; result is in
a slower heart rate as ventricles contract at
their own rate
•Arrythemias are disturbance in heart rhythm
•Fibrillation—a rapid, uncoordinated
shuddering of the heart muscle, it may be
atrial (150b/m) or ventricular(250b/m)or
more , is fatal
Heart Contractions
•Homeostatic imbalance (continued)
•Tachycardia—rapid heart rate over 100
beats per minute
•Bradycardia—slow heart rate less than 60
beats per minutes
The Heart: Cardiac Cycle & Heart Sounds
•Atria contract simultaneously
•Atria relax, then ventricles contract
•Systole = contraction
•Diastole = relaxation
The Heart: Cardiac Output
•Cardiac output (CO)
•Amount of blood pumped by each side
(ventricle) of the heart in one minute
•Stroke volume (SV)
•Volume of blood pumped by each ventricle in
one contraction (each heartbeat)
•Usually remains relatively constant
•About 70 mL of blood is pumped out of the left
ventricle with each heartbeat
•Heart rate (HR)
•Typically 75 beats per minute
The Heart: Regulation of Heart Rate
•Increased heart rate
•Sympathetic nervous system
•Crisis
•Low blood pressure
•Hormones
•Epinephrine
•Thyroxine
•Exercise
•Decreased blood volume
The Heart: Regulation of Heart Rate
•Decreased heart rate
•Parasympathetic nervous system
•High blood pressure or blood volume
•Decreased venous return
Blood Vessels: The Vascular System
•Transport blood to the tissues and back
•Carry blood away from the heart
•Arteries
•Arterioles
•Exchanges between tissues and blood
•Capillary beds
•Return blood toward the heart
•Venules
•Veins
(a)
Artery
Vein
Figure 11.10a
Blood Vessels: Microscopic Anatomy
•Three layers (tunics)
•Tunic intima
•Endothelium
•Tunic media
•Smooth muscle
•Controlled by sympathetic nervous system
•Tunic externa
•Mostly fibrous connective tissue
Valve
Tunica intima
• Endothelium
• Loose connective tissue
Internal elastic
lamina
Tunica media
• Smooth muscle
• Elastic fibers
External elastic lamina
Tunica externa
• Collagen fibers
Lumen
Artery
Venule
Arteriole
Capillary
network
Lumen
Vein
Basement membrane
Endothelial cells
(b)
Capillary
Figure 11.10b
Structural Differences Among Blood
Vessels
•Arteries have a thicker tunica media than
veins
•Capillaries are only one cell layer (tunica
intima) to allow for exchanges between blood
and tissue
•Veins have a thinner tunica media than
arteries
•Veins also have valves to prevent backflow
of blood
•Lumen of veins are larger than arteries
Venous Aids for the Return of Blood to
the Heart
•Veins:
•Have a thinner tunica media
•Operate under low pressure
•Have a larger lumen than arteries
•To assist in the movement of blood back to the
heart:
•Larger veins have valves to prevent
backflow
•Skeletal muscle “milks” blood in veins
toward the heart
Valve (open)
Contracted
skeletal
muscle
Valve (closed)
Vein
Direction of
blood flow
Figure 11.11
Capillary Beds
•Capillary beds consist of two types of vessels
•Vascular shunt—vessel directly connecting
an arteriole to a venule
•True capillaries—exchange vessels
•Oxygen and nutrients cross to cells
•Carbon dioxide and metabolic waste
products cross into blood
Vascular shunt
Precapillary sphincters
True
capillaries
Terminal arteriole
Postcapillary
venule
(a) Sphincters open; blood flows through true
capillaries.
Figure 11.12a
Figure 11.12b
Major Arteries of System Circulation
•Aorta
•Largest artery in the body
•Leaves from the left ventricle of the heart
•Regions
•Ascending aorta—leaves the left ventricle
•Aortic arch—arches to the left
•Thoracic aorta—travels downward through
the thorax
•Abdominal aorta—passes through the
diaphragm into the abdominopelvic cavity
Major Arteries of System Circulation
•Arterial branches of the ascending aorta
•Right and left coronary arteries serve the
heart
Major Arteries of Systemic Circulation
•Arterial branches of the aortia arch (BCS)
•Brachiocephalic trunk splits into the
•Right common carotid artery
•Right subclavian artery
•Left common carotid artery splits into the
•Left internal and external carotid arteries
•Left subclavian artery branches into the
•Vertebral artery
•In the axilla, the subclavian artery becomes
the axillary artery  brachial artery  radial
and ulnar arteries
Major Veins of Systemic Circulation
•Superior and inferior vena cava enter the right
atrium of the heart
•Superior vena cava drains the head and
arms
•Inferior vena cava drains the lower body
3.Fetal Circulation
•Fetus receives exchanges of gases, nutrients,
and wastes through the placenta
•Umbilical cord contains three vessels
•Umbilical vein—carries blood rich in
nutrients and oxygen to the fetus
•Umbilical arteries (2)—carry carbon dioxide
and debris-laden blood from fetus to
placenta
Superior vena cava
Ductus arteriosus
Pulmonary artery
Pulmonary veins
Foramen ovale
Inferior vena cava
Hepatic vein
Ductus venosus
Inferior vena cava
Hepatic portal vein
Umbilical vein
Fetal umbilicus
Umbilical cord
Umbilical arteries
KEY:
High oxygenation
Moderate oxygenation
Low oxygenation
Very low oxygenation
Aorta
Common iliac artery
External iliac artery
Internal iliac artery
Urinary bladder
Placenta
Figure 11.16
Fetal Circulation
•Blood flow bypasses the liver through the
ductus venosus and enters the inferior vena
cava  right atrium of heart
•Blood flow bypasses the lungs
•Blood entering right atrium is shunted
directly into the left atrium through the
foramen ovale
•Ductus arteriosus connects the aorta and
pulmonary trunk (becomes ligamentum
arteriosum at birth)
4.Hepatic Portal Circulation4.
•Veins of hepatic portal circulation drain
•Digestive organs
•Spleen
•Pancreas
• Portal vein carries this blood to the liver
•Liver helps maintain proper glucose, fat, and
protein concentrations in blood,& remove
toxins from blood.
Hepatic Portal Circulation
•Major vessels of hepatic portal circulation
•Inferior and superior mesenteric veins(small
& large intestine)
•Splenic vein(spleen)
•Left gastric vein(stomach)
•Then blood returns to IVC via hepatic vein.
Inferior vena cava
(not part of hepatic
portal system)
Gastric veins
Liver
Spleen
Stomach
Hepatic portal vein
Splenic vein
Inferior
mesenteric vein
Superior
mesenteric vein
Small intestine
Large intestine
Figure 11.18
Pulse
•Pulse
•Pressure wave of blood
•Monitored at “pressure points” in arteries
where pulse is easily palpated
•Pulse averages 70 to 76 beats per minute
at rest
Superficial temporal artery
Facial artery
Common carotid artery
Brachial artery
Radial artery
Femoral artery
Popliteal artery
Posterior tibial
artery
Dorsalis pedis
artery
Figure 11.19
Blood Pressure
•Measurements by health professionals are
made on the pressure in large arteries
•Systolic—pressure at the peak of ventricular
contraction
•Diastolic—pressure when ventricles relax
•Write systolic pressure first and diastolic last
(120/80 mm Hg)
•Pressure in blood vessels decreases as
distance from the heart increases
Variations in Blood Pressure
•Normal human range is variable
•Normal
•140 to 110 mm Hg systolic
•80 to 75 mm Hg diastolic
•Hypotension
•Low systolic (below 110 mm Hg)
•Often associated with illness
•Hypertension
•High systolic (above 140 mm Hg)
•Can be dangerous if it is chronic
The Lymphatic System
•Consists of two semi-independent parts
•Lymphatic vessels
•Lymphoid tissues and organs
•Lymphatic system functions
•Transports escaped fluids back to the blood
•Plays essential roles in body defense and
resistance to disease
Lymphatic Characteristics
•Lymph—excess tissue fluid carried by
lymphatic vessels
•Properties of lymphatic vessels
•One way system toward the heart
•No pump
•Lymph moves toward the heart
•Milking action of skeletal muscle
•Rhythmic contraction of smooth muscle in
vessel walls
Lymphatic Vessels
•Lymph capillaries
•Fluid leaks into lymph capillaries
•Fluid is forced along the vessel
Tissue fluid
Tissue cell
Lymphatic
capillary
Blood
capillaries
Arteriole
Venule
(a)
Figure 12.2a
Lymphatic Vessels
•Lymphatic collecting vessels
•Collect lymph from lymph capillaries
•Carry lymph to and away from lymph nodes
•Return fluid to circulatory veins near the
heart
•Right lymphatic duct
•Thoracic duct
Regional
lymph nodes:
Entrance of right
lymphatic duct into right
subclavian vein
Cervical
nodes
Axillary
nodes
Internal jugular vein
Thoracic duct
entry into left
subclavian vein
Thoracic duct
Aorta
Spleen
Inguinal
nodes
Cisterna chyli (receives
lymph drainage from
digestive organs)
Lymphatics
KEY:
Drained by the right lymphatic duct
Drained by the thoracic duct
Figure 12.3
Lymph
•Harmful materials that enter lymph vessels
•Bacteria
•Viruses
•Cancer cells
•Cell debris
Lymph Nodes
•Filter lymph before it is returned to the blood
•Defense cells within lymph nodes
•Macrophages—engulf and destroy foreign
substances
•Lymphocytes—provide immune response to
antigens
Lymph Node Structure
•Most are kidney-shaped and less than 1 inch
long
•Cortex
•Outer part
•Contains follicles—collections of
lymphocytes
•Medulla
•Inner part
•Contains phagocytic macrophages
Afferent
lymphatic
vessels
Germinal
center in
follicle
Capsule
Subcapsular
sinus
Trabecula
Afferent
lymphatic
vessels
Cortex
Follicle
Efferent
lymphatic
vessels
Hilum
Medullary sinus
Medullary cord
Figure 12.4
Flow of Lymph Through Nodes
•Lymph enters the convex side through afferent
lymphatic vessels(5-7)
•Lymph flows through a number of sinuses
inside the node
•Lymph exits through efferent lymphatic
vessels(1-2)
•Fewer efferent than afferent vessels causes
flow to be slowed
Other Lymphoid Organs
•Several other organs contribute to lymphatic
function
•Spleen
•Thymus
•Tonsils
•Peyer’s patches
Tonsils (in
pharyngeal region)
Thymus (in thorax;
most active during
youth)
Spleen (curves
around left side of
stomach)
Peyer’s patches
(in intestine)
Appendix
Figure 12.5
Spleen
•Located on the left side of the abdomen
•Filters blood
•Destroys worn out blood cells
•Forms blood cells in the foetus
•Acts as a blood reservoir
•Has structure similar to lymph nodes
Thymus Gland
•Located low in the throat, overlying the heart
•Functions at peak levels only during childhood
•Produces hormones (like thymosin) to
program lymphocytes(T cells)
Tonsils
•Small masses of lymphoid tissue around the
pharynx
•Trap and remove bacteria and other foreign
materials
•Tonsillitis is caused by congestion with
bacteria
•Palatine, pharyngeal(adenoids), lingual & tubal
Peyer’s Patches
•Found in the wall of the small intestine
•Resemble tonsils in structure
•Capture and destroy bacteria in the intestine
Body Defenses
•The body is constantly in contact with bacteria,
fungi, and viruses
•The body has two defense systems for foreign
materials
•Innate (nonspecific) defense system
•Adaptive (specific) defense system
•Immunity—specific resistance to disease
Figure 12.6
1.Innate (Nonspecific) Body Defences
•Innate body defenses are mechanical barriers
to pathogens such as
•Body surface coverings
•Intact skin
•Mucous membranes
•Specialized human cells
•Chemicals produced by the body
Surface Membrane Barriers:
A)First Line of Defence
•Skin and mucous membranes
•Physical barrier to foreign materials
•Also provide protective secretions
•pH of the skin is acidic to inhibit bacterial
growth
•Sebum is toxic to bacteria
•Vaginal secretions are very acidic
Surface Membrane Barriers:
First Line of Defense
•Stomach mucosa
•Secretes hydrochloric acid
•Has protein-digesting enzymes
•Saliva and lacrimal fluid contain lysozymes, an
enzyme that destroy bacteria
•Mucus traps microogranisms in digestive and
respiratory pathways
Innate (Nonspecific) Defense System
Cells and Chemicals: B)Second Line of
Defense
•a.Natural killer cells
•b.Inflammatory response
•c.Phagocytes
•d.Antimicrobial proteins
•e.Fever
Innate (Nonspecific) Defense System
Cells and Chemicals: Second Line of
Defense
•a.Natural killer (NK) cells
•Can lyse (disintegrate or dissolve) and kill
cancer cells
•Can destroy virus-infected cells& bacteria.
Innate (Nonspecific) Defense System
Cells and Chemicals: Second Line of
Defense
•b.Inflammatory response
•Triggered when body tissues are injured
•Four most common S&S of acute inflammation
•Redness
•Hotness
•Terndenss
•Edema
Innate (Nonspecific) Defense System
Cells and Chemicals: Second Line of
Defense
•Functions of the inflammatory response
•Prevents spread of damaging agents
•Disposes of cell debris and pathogens
through phagocytosis
•Sets the stage for repair
Innate (Nonspecific) Defense System
Cells and Chemicals: Second Line of
Defense
•Process of the inflammatory response:
•Neutrophils migrate to the area of
inflammation by rolling along the vessel wall
•They squeeze through the capillary walls by
diapedesis to sites of inflammation
•Neutrophils gather in the site of tissue injury
(positive chemotaxis) and consume any
foreign material present.
Innate (Nonspecific) Defense System
Cells and Chemicals: Second Line of
Defense
•c.Phagocytes
•Cells such as neutrophils and macrophages
•Engulf foreign material into a vacuole
•Enzymes from lysosomes digest the
material
Innate (Nonspecific) Defense System
Cells and Chemicals: Second Line of
Defense
•Phagocytosis
•Neutrophils move by diapedesis to clean up
damaged tissue and/or pathogens
•Monocytes become macrophages and
complete disposal of cell debris
Figure 12.9a
1 Phagocyte
adheres to
pathogens.
Phagosome
(phagocytic
vesicle)
Lysosome
Acid
hydrolase
enzymes
(b) Events of phagocytosis
2 Phagocyte
engulfs the
particles,
forming a
phagosome.
3 Lysosome
fuses with the
phagocytic
vesicle, forming a
phagolysosome.
4 Lysosomal
enzymes digest
the pathogens
or debris,
leaving a
residual body.
5 Exocytosis of
the vesicle
removes
indigestible and
residual material.
Figure 12.9b
Cells and Chemicals: Second Line of
Defense
•d.Antimicrobial proteins
•Attack microorganisms
•Hinder reproduction of microorganisms
•Most important
•Complement proteins
•Interferon, used now in treatment of Hip. B
Cells and Chemicals: Second Line of
Defense
•Complement proteins
•A group of at least 20 plasma proteins
•Activated when they encounter and attach to
cells (complement fixation)
•Damage foreign cell surfaces
•Release vasodilators and chemotaxis
chemicals, cause opsonization
Membrane attack
complex forming
Antibodies
attached to
pathogen’s
membrane
Pore
Activated complement proteins attach to pathogen’s
membrane in step-by-step sequence, forming a
membrane attack complex (a MAC attack).
MAC pores in the
membrane lead to
fluid flows that cause
cell lysis.
Figure 12.10
Cells and Chemicals: Second Line of
Defense
•Interferon
•Proteins secreted by virus-infected cells
•Bind to healthy cell surfaces to interfere with
the ability of viruses to multiply
Cells and Chemicals: Second Line of
Defense
•e.Fever
•Abnormally high body temperature
•Hypothalamus heat regulation can be reset
by pyrogens (secreted by white blood cells)
•High temperatures inhibit the release of iron
and zinc from the liver and spleen needed
by bacteria
•Fever also increases the speed of tissue
repair, through vasodilation
Adaptive Defence System :C. Third Line of
Defence
•Immune response is the immune system’s
response to a threat
•Immunology is the study of immunity
•Antibodies are proteins that protect from
pathogens
Adaptive Defense System: Third Line of
Defense
•Types of Immunity
•Humoral immunity = antibody-mediated
immunity
•Provided by antibodies present in body
fluids, made by B lymphocytes
•Cellular immunity = cell-mediated immunity
•Targets virus-infected cells, cancer cells,
and cells of foreign grafts
•Made by T lymphocytes
Adaptive Defense System: Third Line of
Defense
•Antigens
•Any substance capable of exciting the
immune system and provoking an immune
response
•Examples of common antigens
•Foreign proteins (strongest)
•Nucleic acids
•Large carbohydrates
•Some lipids
•Pollen grains
•Microorganisms
Humoral Immune Response
•Most B cells become plasma cells
•Produce antibodies to destroy antigens
•Activity lasts for 4 or 5 days
•Some B cells become long-lived memory cells
(secondary humoral response)
Humoral Immune Response
•Memory B- cells are long-lived
•A second exposure causes a rapid response
•The secondary response is stronger and
longer lasting
Primary Response
(initial encounter
with antigen)
Activated B
cells
Proliferation to
form a clone
Plasma
cells
Antigen
Antigen binding
to a receptor on a
specific B cell
(B cells with
non-complementary
receptors remain
inactive)
Memory
B cell
Secreted
antibody
molecules
Secondary Response
(can be years later)
Clone of cells
identical to
ancestral cells
Subsequent
challenge
by same
antigen results
in more rapid
response
Plasma
cells
Secreted
antibody
molecules
Memory
B cells
Figure 12.12
Relative antibody concentration
in blood plasma
Secondary
response
Primary
response
0
1
2
3
4
5
6
Time (weeks)
Antigen
injected
Antigen
injected
Figure 12.13
Active Immunity
•Occurs when B cells encounter antigens and
produce antibodies
•Active immunity can be
•Naturally acquired during bacterial and viral
infections as in measles & chicken pox
•Artificially acquired from vaccines as in flue
shots by injecting weak bact. Or virus
Passive Immunity
•Occurs when antibodies are obtained from
someone else
•Conferred naturally from a mother to her
featus (naturally acquired)
•Conferred artificially from immune serum or
gamma globulin (artificially acquired)as
antetanic serum.”
e.g. Measles
& Chicken
Pox
e.g. Flu
Shot
Inherited Immunity
e.g. Antetetanic
Serum, AntiSnake Venom
Figure 12.14
Antibodies (Immunoglobulins or Igs)
•Soluble proteins secreted by B cells (plasma
cells)
•Carried in blood plasma
•Capable of binding specifically to an antigen
Figure 12.15a
Antibodies
•Antibody classes
•Antibodies of each class have slightly different
roles
•Five major immunoglobulin classes (MADGE)
•IgM—can fix complement
•IgA—found mainly in mucus
•IgD—important in activation of B cell
•IgG—can cross the placental barrier and fix
complement
•IgE—involved in allergies
Antibodies
•Antibody function
•Antibodies inactivate antigens in a number
of ways
•Complement fixation
•Neutralization
•Agglutination
•Precipitation
Figure 12.16
Cellular (Cell-Mediated) Immune Response
•Antigens must be presented by macrophages
to an immunocompetent T cell (antigen
presentation)
•T cells must recognize the antigen
•After antigen binding, clones form as with B
cells, but different classes of cells are
produced: helper, memory & killer T cells
“Presented”
antigen
T cell antigen
receptor
Antigen
Cytotoxic
(killer)
T cell
Cell-mediated
immunity
(attack on
infected cells)
B cell
Humoral
immunity
(secretion of
antibodies by
plasma cells)
Helper
T cell
Dendritic cell
Cytokines
Antigen
processing
Selfprotein
Cytokines
Figure 12.17
Cellular (Cell-Mediated) Immune Response
•T cell clones
1.Cytotoxic (killer) T cells
•Specialize in killing infected cells
•Insert a toxic chemical (perforin)
2.Helper T cells
•Help other cells( B & T cells) to fight the
invaders
•3. memory T cells
Figure 12.19
Organ Transplants and Rejection
•Major types of grafts
•Autografts—tissue transplanted from one
site to another on the same person
•Isografts—tissue grafts from an identical
person (identical twin)
•Allografts—tissue taken from an unrelated
person ,same species
•Xenografts—tissue taken from a different
animal species
Organ Transplants and Rejection
•Autografts and isografts are ideal donors
•Xenografts are never successful
•Allografts are more successful with a closer
tissue match
Disorders of Immunity:
Allergies (Hypersensitivity)
•Abnormal, vigorous immune responses
•Types of allergies
•1.Immediate hypersensitivity
•Triggered by release of histamine from
IgE binding to mast cells
•Reactions begin within seconds of contact
with allergen
•E.g. Anaphylactic shock—dangerous,
systemic response, as bee stings ,
penicillin allergy
Disorders of Immunity:
Allergies (Hypersensitivity)
•Types of allergies (continued)
•2.Type II: Cytotoxic Hypersensitivity
•Triggered by the release of lymphokines
from activated helper T cells
•Symptoms usually appear 1–3 days after
contact with antigen
•IgM/IgG, are responsible
•E.g. drug induced hemolytic anemia,
granulocytopenia, thrombocytopenia
Disorders of Immunity:
Allergies (Hypersensitivity)
•3.Type III : Immune complex hypersensitivity
•IgG/IgM
•E.g.: Systemic Lupus Erythematosus,
Lupus Nephritis
•Type IV : Cell Mediated/Delayed type
hypersensitivity
•IgA
•E.g.:TB, Leprosy, Blastomycosis,
toxoplasmosis, histoplasmosis
Disorders of Immunity:
Immunodeficiencies
•Production of immune cells is abnormal
•May be congenital or acquired
•Includes AIDS (Acquired Immune Deficiency
Syndrome)
Disorders of Immunity:
Autoimmune Diseases
•The immune system does not distinguish
between self and nonself
•The body produces antibodies and sensitized
T lymphocytes that attack its own tissues
Disorders of Immunity:
Autoimmune Diseases
•Examples of autoimmune diseases
•Multiple sclerosis—white matter of brain and
spinal cord are destroyed
•Myasthenia gravis—impairs communication
between nerves and skeletal muscles
•Type I diabetes mellitus—destroys
pancreatic beta cells that produce insulin
Disorders of Immunity:
Autoimmune Diseases
•Examples of autoimmune diseases
•Rheumatoid arthritis—destroys joints
•Systemic lupus erythematosus (SLE)
•Affects kidney, heart, lung, and skin
•Glomerulonephritis—impairment of renal
function