MEDICAL
HEART AND PERICARDIUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Isovolumetric contraction
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End-diastolic volume
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End-systolic volume
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None of the above
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Detailed explanation-1: -During the early stages of ventricular diastole, both the atrioventricular and semilunar valves are closed. During this phase, there is no change in the amount of blood in the ventricle, but there is a precipitous fall in the intraventricular pressure. This is known as isovolumetric relaxation.
Detailed explanation-2: -Isovolumetric relaxation (d-e): When the ventricular pressures drop below the diastolic aortic and pulmonary pressures (80 mmHg and 10 mmHg respectively), the aortic and pulmonary valves close producing the second heart sound (point d).
Detailed explanation-3: -Meaning of Isovolumetric Contraction Atrioventricular valves close as diastole ends and ventricular pressure rises due to contraction, preventing atria from being recirculated. The aortic and pulmonary semilunar valves are also closed at this point, which corresponds to the R peak on an ECG.