what is the main function of heart valves
The heart valves function like one-way doors which allow blood flow through in the forward direction but prevent the backward flow of blood. Venous blood returns from the body to the right side of the heart which pumps the blood to the lungs. The oxygen-rich blood returns from the lungs to the left side of the heart. The left side of the heart pumps blood to the entire body. As you would expect, the left side of the heart must generate a much greater pressure to pump the blood to the body. On the left side the valves are called mitral and aortic valves.