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Multiple Choice
During which phase of the cardiac cycle is atrial pressure greater than ventricular pressure?
A
Atrial systole
B
Isovolumetric relaxation
C
Isovolumetric contraction
D
Ventricular ejection
Verified step by step guidance
1
Understand the cardiac cycle phases: The cardiac cycle consists of several phases, including atrial systole, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation.
Identify atrial systole: During atrial systole, the atria contract, pushing blood into the ventricles. This is the phase where atrial pressure is typically greater than ventricular pressure.
Consider isovolumetric contraction: In this phase, the ventricles begin to contract with no change in volume because all heart valves are closed. Ventricular pressure rises but is still lower than aortic pressure.
Examine ventricular ejection: During this phase, the ventricles contract and eject blood into the aorta and pulmonary artery. Ventricular pressure is higher than atrial pressure.
Review isovolumetric relaxation: This phase occurs after ventricular ejection when the ventricles relax, and pressure falls. Atrial pressure is not greater than ventricular pressure during this phase.