GENERAL ANATOMY
CARDIOVASCULAR SYSTEM
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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: -This sound comes from the valves shutting on the blood inside the heart. The first sound (the lub) happens when the mitral and tricuspid valves close. The next sound (the dub) happens when the aortic and pulmonary valves close after the blood has been squeezed out of the heart.
Detailed explanation-2: -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-3: -Summary. The familiar ‘lub-dub’ sound of the heartbeat is caused by the rhythmic closing of the heart valves as blood is pumped in and out of the chambers. A heart murmur is a whooshing, humming or rasping sound between the heartbeat sounds. This is caused by noisy blood flow within the heart.
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.