The first heart sound ("lubb") is associated with
A) atrial systole.
B) closing of the atrioventricular valves.
C) opening of the atrioventricular valves.
D) closing of the semilunar valves.
E) opening of the semilunar valves.

Question

Quizplus · Accepted Answer

The first heart sound ("lubb") is caused by the closure of the atrioventricular valves (mitral and tricuspid), which occurs at the beginning of ventricular systole.

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