SCIENCE
CIRCULATORY SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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aorta
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Lub-dub
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vein
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vessels
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Detailed explanation-1: -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-2: -A heart murmur is a blowing, whooshing, or rasping sound heard during a heartbeat. The sound is caused by turbulent (rough) blood flow through the heart valves or near the heart.
Detailed explanation-3: -Etymology. The low-pitched, longer first heart sound forms lub. The higher-pitched, shorter second heart sound forms dub.
Detailed explanation-4: -The first sound “LUBB” is produced when the atrioventricular (tricuspid and bicuspid) valves get closed sharply at the beginning of ventricular systole. The second “DUP” sound is produced at the start of ventricular diastole. The semilunar (pulmonary and aortic) valves get closed.