How is the first heart sound (S1) created?
A) Pulmonic and tricuspid valves close.
B) Mitral and aortic valves close.
C) Aortic and pulmonic valves close.
D) Mitral and tricuspid valves close.

Question

Quizplus · Accepted Answer

The first heart sound (S1) is made by the closing of the mitral (M1) and tricuspid (T1) valves. The pulmonic and tricuspid valves are the valves of the right side of the heart, and they do not close simultaneously in the cardiac cycle. The mitral and aortic valves are the valves of the left side of the heart, and they do not close simultaneously in the cardiac cycle. The aortic and pulmonic valves are the semilunar valves that create the second heart sound.

How Is the First Heart Sound (S1) Created