Which statement is correct with regarding to the cardiac cycle ?The pause between the end of the second heart sound and the beginning of the first heart sound coincides with ventricular diastoleDuring ventricular systole, atrioventricular valves open and semilunar valves closeFrom the atria nearly 70% of the blood flows into the ventricles during atrial systoleThe first heart sound is of shorter duration and created by the closure of the semilunar valves.

The correct statement regarding the cardiac cycle is:

• The pause between the end of the second heart sound and the beginning of the first heart sound coincides with ventricular diastole.

Explanation:

1. During ventricular systole, atrioventricular valves open and semilunar valves close: This statement is incorrect. During ventricular systole, the atrioventricular valves (mitral and tricuspid valves) actually close to prevent blood from flowing back into the atria, while the semilunar valves (aortic and pulmonary valves) open to allow blood to be ejected from the ventricles.

2. From the atria, nearly 70% of the blood flows into the ventricles during atrial systole: This statement is incorrect. During atrial systole, the atria contract and push blood into the ventricles. However, only about 20-30% of the blood flows into the ventricles during this phase. The majority of blood flow into the ventricles occurs passively during ventricular diastole.

3. The first heart sound is of shorter duration and created by the closure of the semilunar valves: This statement is incorrect. The first heart sound (S1) is actually longer in duration and is created by the closure of the atrioventricular valves (mitral and tricuspid valves) at the beginning of ventricular systole. The closure of the semilunar valves (aortic and pulmonary valves) occurs later and creates the second heart sound (S2).

Therefore, the correct statement is that the pause between the end of the second heart sound and the beginning of the first heart sound coincides with ventricular diastole.