The mammalian heart consists of four chambers, two auricles and two ventricles. Typically, one larger blood vessel is connected to each of these chambers. The arota leaves the left ventricle and the branches of this vessel supply all parts of the body with arterial or oxygen rich food. Venous blood collected from all body regions returns through the vena cava into the right auricle. The right auricle is connected with the right ventricle through the tricupsid valve, an opening with three flaps. This valve allows blood to flow from the auricle to ventricle but not in the reverse direction.
Venous blood collected in the right ventricle leaves this chamber via pulmonary artery leading to lungs where the blood is oxygenated and arterial blood returns through the pulmonary vein into the left auricle. A bicupsid valve, equipped with two flaps, separates the left auricle from the left ventricle.
There exists four valves, tricuspide, pulmonary, aortic and mitral, each of them having three laps, except mitral valve, with two laps, instead of three.
The tricuspid valve separates the right ventricle and the right atrium, the pulmonary valve separates the right ventricle and pulmonary artery, the aortic valve separates aorta and the left ventricle and mitral valve separates the left ventricle and the left atrium.
The valves wiork at alternating times, such that: the contraction of left ventricle opens the aortic valve for the blood to flow into aorta, the relaxation of left ventricle opens the mitral valve, while the aortic valve closes and the blood enters form the left atrium to the left ventricle.
The malfunction of valves can create abnormalities in circuit of blood through the body.