What is the relaxed phase of the heartbeat called?

The relaxed phase of the heartbeat is known as diastole. During this phase, the heart muscle relaxes after contraction, allowing the chambers of the heart—the atria and ventricles—to fill with blood. This is a crucial part of the cardiac cycle, as it ensures that the heart has enough blood to pump out to the body during the next contraction, known as systole.

Diastole is characterized by a decrease in pressure within the heart, which facilitates the flow of blood from the veins into the heart chambers. This relaxation phase is vital for the overall efficiency of the heart, enabling it to maintain adequate circulation and oxygenation of tissues throughout the body. In contrast, systole represents the phase when the heart contracts and pumps blood out. Understanding these phases helps in comprehending how the heart functions as a pump, maintaining a consistent and effective blood flow.