During the cardiac cycle, the period of isovolumetric contraction ends when which of the following events occurs?
- A Mitral valve closes
- B Aortic valve opens ✓
- C Tricuspid valve opens
- D Pulmonary valve closes
Correct answer: B. Aortic valve opens
Explanation
Isovolumetric contraction is the brief phase after mitral valve closure during which ventricular pressure rises rapidly without any change in volume. It ends when intraventricular pressure exceeds aortic diastolic pressure, causing the aortic valve to open and ejection to begin. During this phase, both the mitral and aortic valves are closed.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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