The second heart sound,"dup," is caused by the
A)closing of the AV valves.
B)closing of the mitral valve.
C)closing of the semilunar valves.
D)contraction of the ventricles.

Question

Quizplus · Accepted Answer

The second heart sound, "dup," is caused by the closing of the semilunar valves (pulmonary and aortic), which prevent blood from flowing back into the ventricles after they have contracted. The AV valves (mitral and tricuspid) close during the first heart sound, "lub." The contraction of the ventricles does not cause the second heart sound.

The Second Heart Sound,"dup," Is Caused by the