What is the diastolic phase of the heart cycle?

The diastolic phase of the heart cycle refers to the period when the heart muscle relaxes. During this phase, the chambers of the heart—specifically the atria and ventricles—fill with blood in preparation for the next heartbeat. This relaxation allows the heart to receive blood from the body and the lungs, ensuring that it is adequately filled before it contracts again in the systolic phase, where the heart pumps blood out to the rest of the body.

In contrast, the systolic phase is characterized by the contraction of the heart, pushing blood out into the arteries. Understanding the distinction between these two phases is crucial for comprehending how the heart functions as a pump and maintains circulation throughout the body.