During the cardiac cycle the opening of the aortic valve takes place at the
Ans. (b) End of isovolumetric contractionRef: Ganong, 25th ed/p.540Isovolumetric contraction#To eject blood into aorta and pulmonary artery, ventricles must open aortic and pulmonary valve#The sole purpose of this phase is to open these valves#The ventricle contracts against the closed valves (both AV valves and semilunar valves are closed)#This means that ventricular blood volume won't change (isovolumetric) but the pressure generated by the ventricle tremendously rises.#Once the pressure rises above 80 mm Hg, aortic valve opens. Similar changes also happen in right ventricle which opens the pulmonary valve
Beginning of systole
End of isovolumetric contraction
End of diastole
End of diastasis
Heart, Circulation, and Blood