Heart valve tricuspid valve has anterior, posterior, and septal cusps; and the mitral valve has just anterior and posterior cusps. The valves of the human heart can be grouped in two sets: 1- Two Atrioventricular (AV) valves to prevent backflow of blood from the ventricles into the atria a) Tricuspid valve, located between the right atrium and right ventricle. b) Bicuspid or mitral valve, located between the left atrium and left ventricle. 2- Two Semilunar valves to prevent the backflow of blood into the ventricle a) Pulmonary semilunar valve, located at the opening between the right ventricle and the pulmonary trunk. b)
Third heart sound when heard in a middle-aged or older adult, an S is often a sign of disease, indicating increased ventricular filling due to congestive heart failure or severe mitral or tricuspid regurgitation. S is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by the inflow of blood from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that, during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be