If the beating heart makes a ʺlub-dupʺ sound, the ʺdupʺ sound is caused by
A) the apex of the heart hitting the anterior chest wall.
B) vibrations that result from the semilunar valves slamming shut.
C) a stenotic atrioventricular valve.
D) the large force of the contracting ventricles.

Question

Quizplus · Accepted Answer

The "dup" sound is caused by the closure of the semilunar valves (aortic and pulmonary valves) at the end of ventricular systole, resulting in vibrations that produce this sound.

If the Beating Heart Makes a ʺLub-Dupʺ Sound, the ʺDupʺ