The first heart sound ("lubb")is associated with
A)closing of the pulmonary valve.
B)closing of the mitral valve.
C)opening of the mitral valve.
D)closing of the aortic valve.
E)opening of the aortic valve.

Question

Quizplus · Accepted Answer

The first heart sound, also known as S1, is caused by the closure of the mitral and tricuspid valves as blood is pumped into the ventricles. This is what produces the "lubb" sound that is heard. Therefore, the best choice is B) closing of the mitral valve.

The First Heart Sound ("Lubb")is Associated with