The function of the atrioventricular valves is to keep blood in the heart flowing in one direction, according to science educator Regina Bailey for About.com. These connect the atria and the ventricles together. They consist of endocardium and connective tissue. Atrioventricular valves are one of two types in the heart, the other being semilunar.
Atrioventricular valves can be further classified into the mitral valve and the tricuspid valve. According to LearnTheHeart.com, the mitral valve is more important in healthy heart function. When patients with recurring tricuspid valve endocarditis have the tricuspid valve removed, they are not likely to develop heart disease. Several diseases involve abnormalities of the mitral valve, including mitral valve prolapse, mitral regurgitation, tricuspid regurgitation and mitral stenosis.
Mitral valve prolapse is a disease of connective tissue causing the valves to prolapse into the left atrium during systole. This can lead to mitral regurgitation, which is the abnormal backflow of blood from the left ventricle to the atrium. Tricuspid regurgitation involves abnormal backflow of blood from the right ventricle to the right atrium. Mitral stenosis is a decrease in the mitral valve area that disrupts normal blood flow from the left atrium to the left ventricle. Tricuspid stenosis is a rare condition that may also develop from an abnormal mitral valve, notes LearnTheHeart.com. It involves abnormal stiffening or immobilization of the tissues of the tricuspid valve.