ANATOMY
CHEST AND CARDIOVASCULAR
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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opening of the pulmonary and aortic valves
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closure of the tricuspid and bicuspid valves
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closure of the pulmonary and aortic valves
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opening of the tricuspid and bicuspid valves
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Detailed explanation-1: -The second heart sound, called S2, makes a “dub” sound caused by the closure of the semilunar (aortic and pulmonary) valves following ventricular systole.
Detailed explanation-2: -There are two heart sounds every cardiac cycle, “lubb” and “dupp". “Lubb” is produced when the bicuspid and the tricuspid valves close shut, while the “dupp” sound is caused due to the closure of semilunar valves.
Detailed explanation-3: -Normal heart sounds come in pairs. The sounds are often described as a constant “lub-dub, lub-dub.” The first “lub-dub” is the sound of the mitral and tricuspid valves closing. The second “lub-dub” is the sound of the aortic and pulmonary valves closing soon after.
Detailed explanation-4: -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). The closing pressure (the diastolic arterial pressure) on the left is 80 mmHg as compared to only 10 mmHg on the right.