Cardiovascular System

Cardiovascular System
The Heart
Location & Size
Size of a fist; less than a pound
 Apex – points to left hip
 Base – points towards right shoulder
Visceral pericardium (epicardium)
– hugs external surface of heart
– part of the heart wall
Parietal pericardium
– anchors the heart to surrounding structures
such as the diaphragm and sternum.
Layers of Heart Wall
Epicardium (visceral pericardium)
– Outer layer
– Layer that contracts
– Thick bundles of cardiac muscle
– Thin sheet of endothelium
– Lines the heart chambers
Atria (2)
– Receiving chambers
Ventricles (2)
– Discharging chambers
Interventricular or interatrial septum –
divides the heart longitudinally
Blood Vessels
Superior & inferior venae cavae
– Receives deoxygenated blood from veins of
the body
Pulmonary trunk
– Receives deoxygenated blood pumped out
from the right ventricle
Blood Vessels
Right and left pulmonary arteries
– Branches off from pulmonary trunk
Pulmonary veins (4)
– Receives oxygenated blood from the lungs
– Receives oxygenated blood pumped out from
the left ventricle
Atrioventricular valves (AV valves)
 Chordae tendineae
 Semilunar valves
Atrioventricular valves (AV valves)
Located between atrium and ventricle
 Prevents backflow into the atria when
ventricles contract
 Bicuspid valve
– Left AV valve
– Consists of two cusps or flaps
Tricuspid valve
– Right AV valve
– Has three cusps
Chordae tendineae
Tiny white
cords that
anchor the
cusps to the
walls of the
Semilunar valves
Each valve has three cusps
– cusps forced open as ventricles contract
– Blood flows back after contraction closing
Pulmonary semilunar valve
– Between right ventricle and pulmonary trunk
Aortic semilunar valve
– Between left ventricle and aorta