Anatomy of the heart
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The heart is located within the bony thorax
and is flanked on each side by lungs.
The apex is directed toward the left hip and
rests on the diaphragm-in 5th intercostal
space.
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The base (posterosuperior aspect),
from which the great vessels of the
body emerge, points toward the right
shoulder and lies beneath the second
rib.
Coverings of the heart
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Double sac of serous membrane, the
pericardium
Thin visceral pericardium, or epicardium
(hugs the external surface of the heartpart of heart wall)
Parietal pericardium, dense fibrous
connective tissues (protect the heartanchors to it’s surrounding structures.
Serous fluid is produced by the serous
pericardial membrane.
Wall of the heart
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Outer epicardium(visceral pericardium)
Myocardium consist of thick bundles of
cardiac muscle twisted (contraction)
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Endocardium is a thin sheet of
endothelium that lines the heart
chambers (continous with lining of
blood vessels)
Chambers and associated vessels
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Two atria and two ventricles.
The superior atria are receiving
chambers.
The inferior,thick-walld ventricles are
discharging chambers (actual pump of
the heart).
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The right ventricle forms most of
anterior surfaces… the left ventricle
forms the apex.
Interatrial or interventricular septum
divides the heart longitudinally.
Valves
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Four valves, which allow blood to flow
in only one direction.
The atrioventricular, or AV valves are
located between the atrial and
ventricular chambers on each side.
The AV valves prevent backflow into the
atria when ventricles contract.
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The AV valve-bicusped or mitral valve
consist of two cusp, or flaps, of
endocardium.
The right AV valve, the tricusped valve,
has three cusps.
Chordae tendineae : tiny white cord –
anchor the cusps to the wall of the
ventricles
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Semilunar valves (three cusps) (pumonary
and aortic valves), guards the bases of two
large arteries leaving the ventricular
chambers.
Cardiac circulation
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Single organ
Heart function as a double pump
Pulmonary circulation
Systemic circulation
Pulmonary circulation
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The right side works as the pulmonary
circuit pump.
It receives oxygen-poor blood from the
veins of the body through superior and
inferior venae cavae and pumps it out
through the pulmonary trunk.
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From pulmonary trunk to right and left
pulmonary arteries , which carry blood
to the lungs, where oxygen is picked up
and carbon dioxide is unloaded
Oxygen-rich blood drains from the lungs
and is returned to the left side of the
heart through the four pulmonary veins.
Function of pulmonary
circulation
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Carry blood to the lungs for gas
exchange
Return it to the heart
Systemic circulation
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Blood returned to the left side of the
heart is pumped out of the heart into
the aorta to systemic arteries branch to
supply all body tissues
Function of the systemic
circulation
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It supplies oxygen- and nutrient-rich
blood to all body organs.
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Hepatic Portal circulation;
blood flows from GIT to the
liver via portal vein then to
systemic circulation via IVC
Blood supply of the heart
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Coronary arteries : are branches from
the base of the aorta and encircle the
heart in the atrioventricular groove
Right coronary artery :posterior
interventricular and marginal arteries
Left coronary artery:anterior
interventricular and circumflex arteries
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Cardiac veins drains into coronary sinus
then to right atrium.