What causes the characteristic heart sounds that a doctor hears when using a stethoscope?
A) The atria contracting
B) The ventricles contracting
C) The closure of the heart valves
D) The opening of the heart valves

Question

Quizplus · Accepted Answer

The characteristic heart sounds, often referred to as "lub-dub," are caused by the closure of the heart valves. The "lub" sound is due to the closure of the atrioventricular valves (mitral and tricuspid), and the "dub" sound is due to the closure of the semilunar valves (aortic and pulmonary).

What Causes the Characteristic Heart Sounds That a Doctor Hears