Ventricular Ejection Phase in Cardiac Cycle

Steps:

• Identify phases: Atrial systole (AV open, semilunar closed), ventricular systole (isovolumetric contraction: both closed; ejection: semilunar open, AV closed), diastole (both open or AV open).
• Match valve states: Semilunar open when ventricular pressure > arterial pressure; AV closed when ventricular pressure > atrial pressure.
• Locate on diagram: Period with rising ventricular pressure above arteries, after isovolumetric contraction.
• Confirm: This occurs during ejection, option C.

Why C is correct:

• During ejection, ventricular pressure exceeds aortic/pulmonary pressure (per pressure-volume relationships), opening semilunar valves while AV valves remain closed due to higher ventricular pressure.

Why the others are wrong:

• A: Atrial systole—AV valves open, semilunar closed.
• B: Isovolumetric contraction—both valve sets closed.
• D: Diastole—both valve sets open.

Final answer: C