MICROANATOMY

Detailed explanation-1: -Eventually, the pressure within the ventricle exceeds the pressure in the arteries, and the aortic valve opens, marking the beginning of rapid ventricular ejection. A healthy ventricle will eject more than 60% of its volume, and after the aortic valve closes, the cycle begins again.

Detailed explanation-2: -As soon as the ventricular pressure falls bellow the atrial pressure, the atrioventricular valves open. Blood flows rapidly from the atria to the ventricles.

Detailed explanation-3: -The opening and closing of the AV valves is dependent on pressure differences between the atria and ventricles. When the ventricles relax, atrial pressure exceeds ventricular pressure, the AV valves are pushed open and Page 2 blood flows into the ventricles.

Detailed explanation-4: -The first heart sound (S1) represents closure of the atrioventricular (mitral and tricuspid) valves as the ventricular pressures exceed atrial pressures at the beginning of systole (point a).