PHYSIOLOGY
CARDIOVASCULAR PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the atria are receiving and upper chambers of the heart
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the ventricles are the pumping and lower chambers of the heart
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the tricuspid and bicuspid valves prevent the backflow of blood into the atria
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the lub sound of the heart in the lub-dub is caused by the closing of the semilunar valves
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Detailed explanation-1: -The first heart sound we hear is caused by the simultaneous closing of the bicuspid (mitral) valve and the tricuspid valve, both atrioventricular valves. It is similar to the word “LUBB” and is created due to the isometric period of contraction and the earlier part of the period of ejection. > Option B is incorrect.
Detailed explanation-2: -The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point d). S2 is normally split because the aortic valve (A2) closes before the pulmonary valve (P2).
Detailed explanation-3: -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.