Question

The second heart sound during the cardiac cycle is produced by the:

• (A) Simultaneous opening of the atrioventricular valves
• (B) Simultaneous closure of the atrioventricular valves
• (C) Simultaneous opening of the semilunar valves
• (D) Simultaneous closure of the semilunar valves

Answer 1

The Correct Option is D

Explanation:
The second heart sound during the cardiac cycle is produced by the simultaneous closure of the semilunar valves.The second heart sound $\left(S_2\right)$ is produced by the closure of the aortic $\left(A_2\right)$ and the pulmonary valves $\left(P_2\right)$ at the end of systole. Refer to the audio example below. $A_2$ is best heard at the aortic area (second right intercostal space); $P_2$ is best heard at the pulmonary area.Hence, the correct option is (D).