What is the function of AV valves?

The atrioventricular (AV) valves, also known as the mitral valve on the left side of the heart and the tricuspid valve on the right side, play essential roles in the heart's function by regulating blood flow and preventing backflow. Here are their functions:

1. One-way flow of blood: The AV valves ensure that blood flows in one direction, from the atria (upper chambers) of the heart to the ventricles (lower chambers) during ventricular filling.

2. Atrioventricular closure: During ventricular contraction (systole), the AV valves close to prevent blood from flowing back into the atria. This is crucial in maintaining effective forward blood circulation and preventing backward movement.

3. Heart sound production: As the AV valves open and close, they create characteristic heart sounds, known as the first heart sound (S1) and second heart sound (S2). These sounds can be detected during auscultation and help medical professionals assess the proper functioning of the heart.

4. Volume control: The AV valves help regulate the volume of blood filling the ventricles during ventricular diastole (relaxation). Adequate filling is necessary for ensuring sufficient stroke volume and cardiac output.

5. Prevention of regurgitation: By closing securely during ventricular systole, the AV valves prevent the backflow of blood from the ventricles back into the atria. Regurgitation, or backward flow, can occur if the valves fail to close properly, leading to inefficient heart function.

Overall, the AV valves play vital roles in maintaining the coordinated blood flow within the heart, ensuring efficient forward circulation and preventing backflow.