Your heart has four chambers: The right and left atria and the right and left ventricles, separated by four valves that control the flow of blood through your heart and the septum, which separates the left side from the the right side of your heart.
The four heart valves are:
- The tricuspid valve, located between the right atrium and right ventricle;
- The pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery;
- The mitral valve, between the left atrium and left ventricle; and
- The aortic valve, between the left ventricle and the aorta.
Each valve has a set of flaps (also called leaflets or cusps). The mitral valve has two leaflets; the others have three. Under normal conditions, the valves permit blood to flow in only one direction. Blood flow occurs only when there’s a difference in pressure across the valves that causes them to open. The mitral and tricuspid valves are connected to small muscles (papillary) along the wall of the heart by small string like tendons (chordeae tendineae). Papillary muscle contraction opens these valves.
The aortic and pulmonic valves are differently shaped and do not have cordae tendineae or papillary muscles.