A heart valve normally allows blood to flow in only one direction through the heart. The four valves are commonly represented in a mammalian heart that determines the pathway of blood flow through the heart. A heart valve opens or closes incumbent on differential blood pressure on each side.The four main valves in the heart are:

The two atrioventricular (AV) valves, the mitral valve (bicuspid valve), and the tricuspid valve, which are between the upper chambers (atria) and the lower chambers (ventricles).
The two semilunar (SL) valves, the aortic valve and the pulmonary valve, which are in the arteries leaving the heart.The mitral valve and the aortic valve are in the left heart; the tricuspid valve and the pulmonary valve are in the right heart.
There are also the coronary sinus and the inferior vena cava valves.