Cardiovascular Function: Anatomy
The heart muscle pumps blood through the circulatory system. Each day, the heart beats 100,000 times and pumps
2000 gal of blood. The heart is composed of 4 chambers (divisions): the upper
two, the right and left atria; the lower two, the right and left ventricles.
Blood is pumped through the chambers, in only 1 direction, via 4 valves: the
tricuspid, located between the right atrium and the right ventricle; the
pulmonary, between the right ventricle and the pulmonary artery; the mitral,
between the left atrium
and the left ventricle; and the aortic, between the left ventricle and the
aorta. Dark blood, low in oxygen, returns from body tissues through veins,
enters the right atrium, and then flows to the right ventricle, the pulmonary
artery, and the lungs, where it is oxygenated. Blood returns by pulmonary veins
to the left atrium and goes through the mitral valve into the left ventricle,
which pumps oxygen-rich, bright-red blood through the aortic valve into the
aorta and then into the circulation.
