The first and second heart sounds are most directly related to
A) pulse pressure in the aorta.
B) the contraction of the atria.
C) vibrations that occur when the valves close.
D) contraction of the papillary muscles.
E) the flow of the blood.

Question

Quizplus · Accepted Answer

The first and second heart sounds are primarily related to the vibrations that occur when the heart valves close. The first sound (S1) is associated with the closure of the mitral and tricuspid valves at the beginning of ventricular systole, while the second sound (S2) is associated with the closure of the aortic and pulmonary valves at the beginning of ventricular diastole.

The First and Second Heart Sounds Are Most Directly Related