Transcript Lab 4: Circulatory System Part II (Anatomy of the Heart)

Dr. Kim Wilson
Part A: Anatomy of the Human
Heart
Anatomy of the Heart
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Reference Exercise 30, pg. 443 - 452
Major Structures of the Human
Heart
Gross Anatomy of the Human
Heart
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Cone-shaped organ, shaped like a fist
Function of cardiovascular system: circulation
(heart pumps blood through the blood vessels)
Heart Orientation
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Apex - directed anteriorly, inferiorly and to the left
Base - directed posteriorly, superiorly and to the right
Anterior surface - deep to the sternum and ribs
Inferior surface - rests on the diaphragm
Right border - faces right lung
Left border (pulmonary border) - faces left lung
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Human Heart
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Location: mediastinum (area from sternum to
vertebral column and between the lungs
 Tip or apex faces left side and
 Top of the heart is the base, faces right side
 Fluid filled sac to protect is pericardium (visceral and
parietal)
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Heart action
 Contraction is systole
 Relaxation is diastole
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Chambers
 Top two chambers are atria where blood enters heart
 Bottom two chambers are ventricles where blood exits
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart - Layers
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Pericardium
 The heart and the proximal ends of the large blood vessels are enclosed
by the pericardium.
Consists of an outer fibrous bag--fibrous pericardium which
surrounds a more delicate double-layered sac – serous
pericardium
 Fibrous pericardium
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 dense irregular CT
 protects and anchors the heart, prevents overstretching
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Serous pericardium
 Inner layer of this sac--visceral pericardium (epicardium) covers the
heart
 At the base of the heart the visceral pericardium turns back on itself to
become the parietal pericardium.
Between the parietal and visceral layers is the pericardial cavity
which contains serous fluid--pericardial fluid.
 The fluid reduces friction between the pericardial membranes
when the heart moves within them
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Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart - Layers
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Layers of the heart wall
 Epicardium
○ visceral layer of serous pericardium
○ Also called visceral pericardium
○ Functions as an outer protective layer
○ Serous membrane that consists of connective tissue covered
by epithelium.
 Myocardium
○ Cardiac muscle layer is the bulk of the heart
○ Relatively thick
○ Consists largely of cardiac muscle tissue responsible for
forcing blood out of the heart chambers.
○ Thickness of myocardium varies according to the function of
the chamber
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart – Layers
cont.
 Endocardium
○ innermost layer, lines chamber & valves
○ Consists of epithelial and connective tissue that
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contains many elastic and collagenous fibers
○ Lines all of the heart chambers and covers heart valves
(is continuous with the inner lining of blood vessels—
endothelium)
Atria are thin walled, deliver blood to adjacent ventricles
Ventricles are thick walled as they pump blood away from
heart
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart - Chambers
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Chambers
Internally, the heart is divided into four (4)
hollow chambers
Upper chambers--atria
Have relatively thin walls and receive blood
from veins.
Lower chambers—ventricles, which force
blood out of the heart into the arteries.
The atrium and ventricle on the right side are
separated from those on the left by the
interatrial septum and interventricular septum
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart – Surface
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The atrium on each side communicates with its corresponding
ventricle through an opening called the atrioventricular orifice
which is guarded by an A-V valve.
Grooves on the surface of the heart mark the divisions between
its chambers and also contain the major coronary arteries
The deepest groove is the coronary sulcus which encircles the
heart between the atrial and ventricular portions. It contains the
coronary sinus
The anterior and posterior interventricular sulci indicate the
location of the septum that separates the right and left
ventricles.
Small ear-like projections--auricles--extend outward from the
atria.
The anterior interventricular sulcus contains the left coronary
artery and the great cardiac vein.
The posterior interventricular sulcus contains the right
coronary artery and middle cardiac vein
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart – Right
Atrium
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Receives blood from the superior vena cava,
inferior vena cava and coronary sinus
 They return blood low in O2 from the body.
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The right atrium and right ventricle are
separated by a large tricuspid valve
 Has three cusps composed of dense CT covered by
endocardium
 Valve permits blood to move from the right atrium
into the right ventricle and prevents it from passing in
the opposite direction
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Interatrial septum partitions the atria
Fossa ovalis is a remnant of the fetal foramen
ovale
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart Atrioventricular Valves
Chordae Tendineae - are attached to the
cusps of the valve.
 Originate from small mounds of muscle
tissue--papillary muscle--which project
into chamber from the wall of the
ventricle.
 When the tricuspid valve closes the
chordae tendineae and papillary
muscles prevent the cusps from
swinging into the atrium.
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Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart – Right
Ventricle
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The right ventricle has a much thicker wall than the right atrium.
The arrangement of muscle is called trabeculae carnae.
The right ventricle has much thinner walls than the left ventricle.
Pumps blood a relatively short distance to the lungs against relatively low
resistance to blood flow.
When the right ventricle contracts, blood in the chamber is subjected to
increasing pressure and the tricuspid valve closes passively.
Pressure changes
Pressure in the right ventricle continues to rise as the ventricle contracts.
This forces the pulmonary semilunar valve leading into the pulmonary
trunk to open
Blood from the right ventricle passes into the pulmonary trunk which divides
to form the right and left pulmonary arteries.
At the base of this trunk is the pulmonary semilunar valve which consists
of three cusps. This valve opens when the right ventricle contracts.
When the right ventricular muscles relax, blood begins to back up causing
the semilunar valve to close. Blood via the pulmonary arteries goes to the
right and left lung where it is oxygenated
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart – Left
Atrium
The left atrium receives blood from four
pulmonary veins (two form the right lung
and two from the left lung).
 Forms most of the base of the heart
 Blood then passes from the left atrium
thru the left atrioventricular valve
which consists of two leaflets and is also
called the bicuspid or mitral valve.
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 Prevents blood from flowing back the left
atrium from the left ventricle
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart – Left
Ventricle
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Forms the apex of heart
Fills with blood from left atrium
Left ventricle begins to contract
When pressure in left ventricle more than that in left
atrium, left AV valve closes
When the left ventricle contracts, the bicuspid valve
closes and the only exit for the blood is through the
aorta.
At the base of the aorta is an aortic semilunar valve
that consists of three cusps.
It opens and allows blood to leave the left ventricle.
When the ventricular muscles relax, this valve closes
and prevents blood from backing up into the
ventricle.
Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart - Aorta
Blood passes through aortic semilunar
valve valve into the ascending aorta
 Just above valve are the openings to the
coronary arteries which supplies the
tissues of the heart
 Branches of the aorta then distribute
blood to all parts of the body.
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Notes courtesy of Dr. Anita Kandula, DeAnza College
Anatomy of the Heart - Valves
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Heart valves to prevent blood backflow between
chambers
Heart valves open and close in response to pressure
changes between the chambers they separate
Atrioventricular (AV) valves
 Between atria and ventricles
 Left is biscuspid or mitral valve
 Right is tricuspid valve
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Semilunar valves
 Between ventricles and major arteries leaving heart
 Right is pulmonary semilunar valve
○ Blood to lung via pulmonary trunk
 Left is aortic semilunar valve
○ Blood to whole body via aorta
Notes courtesy of Dr. Anita Kandula, DeAnza College
Basic Anatomy of the Heart
http://www.yourheartvalve.com/heartbasi
cs/heartanatomy.htm
 Good site to review functions and valves
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Heart, anterior view
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Heart, anterior view
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Heart, anterior view
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Heart, posterior view
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Heart, posterior view
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Heart, Arteries and Veins
(posterior view)
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Heart, anterosuperior view
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Heart, anterosuperior view
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Heart, coronal section
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Heart, right ventricle open
(anterior view)
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Heart valves, superior view
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Heart, right atrium opened,
superior view
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Heart blood vessels, anterior
view
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Heart blood vessels, posterior
view
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Heart blood vessels, lateral view,
right side
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Heart, anteroinferior view
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Heart, Purjunkie Fibers
Specialized conductive
fibers located within the
walls of the ventricles
 Function: relay cardiac
impulses to the cells of
the ventricles, which
allow the ventricles to
contract
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Source: http://lxixixl.com/keyword/cardiac%20muscle%20fibres/
Part B: Anatomy of the Sheep
Heart
Follow diagrams (1-3) in
your lab manual for
dissection procedure of
the sheep heart.
Copyright ©2008 Pearson Education: Image reproduced with permission.
Major Structures of the Sheep
Heart
Sheep Heart Dissection
Brachiocephalic
1 Artery
(Oxygenated)
2 Aortic Arch
. (Oxygenated)
Openings for
3
Pulmonary Veins
.
(Oxygenated)
Opening for
4 Inferior Vena
. Cava
(Deoxygenated)
5
Left Ventricle
.
Opening for
6 Superior Vena
. Cava
(Deoxygenated)
7
Right Auricle
.
8
Right Ventricle
.
Sheep Heart, whole
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Sheep Heart, frontal section
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Sheep Heart, Frontal Section
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Sheep Heart, right side opened,
posterior view
1.
Right Atrium
2.
Right
Ventricle
3.
Myocardium
(Note
Thinness)
4.
Opening of
Coronary
Sinus
5.
Inferior Vena
Cava
6.
Superior
Vena Cava
7.
Pectinate
Muscle
8.
Tricuspid
Valve
9.
Papillary
Muscle
10.
Moderator
Band
Source:
http://homes.bio.psu.edu/people/faculty/strauss/anatomy/circ/rtheartpo
st.htm
Sheep Heart, left side, lateral
view
1.
Pulmonary
Artery
2.
Brachiocephali
c Artery
3.
Aorta
4.
Aortic
Seminlunar
Valve
5.
Opening for
Coronary
Artery
6.
Trabeculae
Carnae of Left
Ventricle
7.
Ventricular
Myocardium
(Note
Thickness)
Source: http://homes.bio.psu.edu/people/faculty/strauss/anatomy/circ/ltheartlat2.htm
Questions
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Useful Web Resources
http://www.gwc.maricopa.edu/class/bio2
02/cyberheart/hartint_.htm
 Animated quiz on the human heart
model
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