NEET2026BiologyChapterActual
A physician using a stethoscope hears two prominent sounds during each cardiac cycle of a healthy individual. The second heart sound is produced primarily due to the:
Options
- Asudden opening of the tricuspid and bicuspid valves during joint diastole.
- Bclosure of the semilunar valves at the beginning of ventricular diastole.
- Cclosure of the atrioventricular valves at the onset of ventricular systole.
- Drapid rushing of blood from the atria into the ventricles.
Correct answer
B. closure of the semilunar valves at the beginning of ventricular diastole.
Step-by-step solution
During each cardiac cycle, two prominent sounds are produced which can be easily heard through a stethoscope. The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves at the beginning of ventricular systole. The second heart sound (dub) is associated with the closure of the semilunar valves at the beginning of ventricular diastole. Answer: closure of the semilunar valves at the beginning of ventricular diastole.