The Cardiovascular System
 composed of the heart, blood vessels and blood
 main functions:
a) delivery of oxygen, fuel and other nutrients to the tissues of the
body, removal of carbon dioxide and waste products from the
tissues
b) maintenance of a constant body temperature (thermoregulation)
c) prevention of infection (immune function)
Heart
 myocardium – cardiac muscle tissue
 heart is a double pump – divided into right and left parts, separated
by the interventricular septum
 role of the right side of the heart – pump deoxygenated (blue) blood,
returned from the body, to the lungs (pulmonary circulation)
 role of the left side of the heart – pump oxygenated (bright red)
blood, just returned from the lungs, to the rest of the body (systemic
circulation)
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pericardium – protective sac, surrounds the heart
epicardium – outer layer of the heart, lies against the pericardium
myocardium – located under the epicardium
endocardium – lines the inside of the heart
 contains 4 chambers – 2 atria which are the upper chambers, and 2
ventricles which are the lower chambers
 atrioventricular (AV) valves – allows blood to flow from the atria
into the ventricles
 the right side of the heart contains the tricuspid valve
 the left side of the heart contains the bicuspid (mitral) valve
 valves are also found where blood leaves the ventricles
 the right side of the heart contains the semilunar valve
 the left side of the heart contains the aortic semilunar valve
Path of Blood through the Heart
1) blood is delivered to the right atrium from the superior and
inferior vena cava
2) the superior vena cava returns blood to the heart from the upper
body
3) the inferior vena cava returns blood from the lower body
4) blood in the right atrium passes through the tricuspid valve and
enters the right ventricle
5) blood is pumped through the pulmonary semilunar valve and out
the pulmonary arteries to the lungs (pulmonary circulation)
6) blood returns from the lungs through the pulmonary veins to the
left atrium
7) blood passes through the bicuspid (mitral) valve and enters into
the left ventricle
8) blood is then pumped out through the aortic semilunar valve into
the aorta and throughout the systemic circulation
9) which eventually returning back to the heart through the inferior
and superior vena cava
 arteries are vessels that carry blood away from the heart while
veins are vessels that carry blood toward the heart
 in systemic circulation, arteries carry oxygenated blood while veins
carry deoxygenated blood
 in pulmonary circulation, pulmonary arteries carry deoxygenated
(blue) blood from the heart to the lungs and pulmonary veins carry
oxygenated (red) blood from the lungs back to the heart