Question

multiple choice question
when a physician listens to heart sounds through a stethoscope, they hear vibrations in heart tissues associated with blood turbulence caused by

• the opening of heart valves
• contractions of the left atrium and the left ventricle
• the rapid movement of blood from atria to ventricles
• the closing of heart valves

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Explanation:

When a physician listens to heart sounds with a stethoscope, the characteristic 'lub - dub' sounds are due to the closing of heart valves. The closing of valves creates vibrations in heart tissues associated with blood turbulence. Opening of valves is relatively quiet, contractions of left atrium and ventricle don't directly produce the main audible sounds, and the rapid movement of blood from atria to ventricles is not the source of the distinct heart sounds heard.

Answer:

D. the closing of heart valves