MEDICAL
HEART AND PERICARDIUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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when pressure inside the ventricles is at its lowest
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when pressure inside the atria is greater than that inside the ventricles
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when ventricular pressure exceeds that of the atria
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when pressure is greater in the aorta than in the left ventricle
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Detailed explanation-1: -The first heart sound (S1) represents closure of the atrioventricular (mitral and tricuspid) valves as the ventricular pressures exceed atrial pressures at the beginning of systole (point a).
Detailed explanation-2: -Immediately after a ventricular contraction begins, the pressure in the ventricles exceeds the pressure in the atria and thus the atrioventricular valves shut.
Detailed explanation-3: -Outflow Phase Once the ventricles’ pressure exceeds the pressure in the aorta/pulmonary trunk, the outflow valves (aortic/pulmonary) open, and blood is pumped from the heart into the great arteries.
Detailed explanation-4: -The aortic valve closes when left ventricular pressure falls below aortic pressure, and momentum briefly maintains forward flow despite greater aortic than left ventricular pressure. Ventricular pressure then declines exponentially during isovolumetric relaxation, when both the aortic and mitral valves are closed.