Heart Sounds and Valve Closure — NEET Biology
✅ Asked in NEET 2024During 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 whereas the second heart sound (dub) is associated with the closure of the semilunar valves. These sounds are of clinical diagnostic significance.
The NTA tests your knowledge of which valves produce which heart sounds. The first sound (lub) comes from tricuspid and bicuspid valve closure during ventricular contraction, while the second sound (dub) comes from semilunar valve closure during ventricular relaxation. Students often confuse which valves produce which sounds or mix up the timing. Remember: lub = AV valves closing (tricuspid + bicuspid), dub = semilunar valves closing (aortic + pulmonary). These are clinically important findings that doctors detect using a stethoscope, making it a high-yield NEET topic.
‘Lub’ sound of heart is caused by the ________.
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