What is the cardiac cycle?

The cardiac cycle refers to the series of events that occur during one complete heartbeat, encompassing the phases of contraction and relaxation of the heart chambers. This cycle includes specific intervals such as atrial systole, ventricular systole, and diastole, during which blood is pumped out of the heart and into circulation, and the heart chambers fill with blood, respectively.

Understanding the cardiac cycle is crucial in cardiovascular physiology, as it illustrates how the heart functions to maintain adequate blood flow and pressure throughout the body during each heartbeat. It highlights the coordinated contractions of the heart’s atria and ventricles, driven by electrical signals that initiate cardiac muscle contractions.

The other options describe aspects related to cardiac function but do not encapsulate the comprehensive nature of the cardiac cycle itself. The recovery time of the heart and periods of rest are important but do not define the complete sequence of mechanical and electrical events that occur in a single heartbeat. The process of electrical conduction is a component of the cardiac cycle but does not represent the entirety of the cycle’s complexity.