In response to a student nurse's question, the nurse correctly states:
A) "The first heart sound reflects the sound produced by relaxation of the atria."
B) "The first heart sound reflects the closing of the mitral and tricuspid valves."
C) "The first heart sound reflects the closing of the pulmonary and aortic valves."
D) "The first heart sound reflects the beginning of the atrial contraction."

Question

Quizplus · Accepted Answer

The first heart sound is commonly known as S1 and is produced by the closure of the mitral and tricuspid valves. This occurs at the beginning of the ventricular systole when the ventricles start to contract and the pressure within them increases, causing the blood to flow toward the aorta and pulmonary artery. The closing of these valves produces a vibration that can be heard as the first heart sound.

In Response to a Student Nurse's Question, the Nurse Correctly