please let me know more about valves.

A heart valve normally allows blood to flow through it in only one direction. There are four in a mammalian heart and they determine the pathway of blood flow through the heart. A heart valve opens or closes depending on the different pressures on each side of it.

Blood is pumped through the chambers, aided by the four heart valves. The valves open and close to let the blood flow in only one direction. The 4 valves are:

- The tricuspid valve between the right atrium and right ventricle.

- The pulmonary valve between the right ventricle and the pulmonary artery.

- The mitral valve between the left atrium and left ventricle.

- The aortic valve is between the left ventricle and the aorta.

Each valve has a set of flaps (or cusps). When working properly, the heart valves open and close fully.