QABiology › Which is the correct sequence of events of the cardiac cycle?

Which is the correct sequence of events of the cardiac cycle?

a. Ventricular filling → isovolumetric relaxation → ventricular ejection → isovolumetric contraction

b. Ventricular filling → isovolumetric contraction → ventricular ejection → isovolumetric relaxation

c. Ventricular filling → isovolumetric contraction → isovolumetric relaxation → ventricular ejection

d. Ventricular filling → isovolumetric relaxation → isovolumetric contraction → ventricular ejection

e. Ventricular filling → ventricular ejection → isovolumetric contraction → isovolumetric relaxation


The cardiac cycle is made up of 4 different stages through which blood flows to and from the heart. Each stage is characterized by movements of the tissues of the heart either in the opening, filling, closing, or emptying the heart of blood. There is a particular pattern that exists in this cycle, and it is as follows:

Ventricular filling, also known as ventricular diastole. Here, the heart opens to receive blood from the lungs and other parts of the body. Next is the isovolumetric relaxation where the heart relaxes for blood to flow into it. The isovolumetric contraction comes next, with the ventricles contract to close the ventricles from receiving any more blood. After this, ventricular ejection, also known as ventricular systole occurs. It is the process where blood is forced or pumped out of the heart. At this point, the heart prepares to relax to start a new cycle.

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