Concerning heart sounds, which of the following is correct?
A) The first heart sound occurs at the beginning of ventricular systole.
B) The second heart sound is heard when the AV valves are closing.
C) The first heart sound is the sound of the semilunar valves closing.
D) The second heart sound occurs when blood flows into the superior vena cava.
E) The first heart sound occurs at the beginning of ventricular diastole.

Question

Quizplus · Accepted Answer

The first heart sound is associated with the closure of the atrioventricular (AV) valves at the beginning of ventricular systole, not the semilunar valves or the beginning of ventricular diastole. This sound is often described as "lub" and marks the start of systole when the ventricles begin to contract.

Concerning Heart Sounds, Which of the Following Is Correct