MICROANATOMY

Detailed explanation-1: -The pressure generated in the ventricles when the heart contracts during systole forces the atrioventricular valve leaflets back toward the atria, whereupon the leaflets meet – or coapt – to seal the annuli and prevent retrograde blood flow from the ventricles back into the atria.

Detailed explanation-2: -Valves open or close based on pressure differences across the valve. The atrioventricular (AV) valves separate the atria from the ventricles on each side of the heart and prevent backflow of blood from the ventricles into the atria during systole.

Detailed explanation-3: -When the ventricles contract, atrioventricular valves close to prevent blood from flowing back into the atria. When the ventricles relax, semilunar valves close to prevent blood from flowing back into the ventricles.