What is the process called when the heart contracts?

The process when the heart contracts is known as systole. During systole, the ventricles of the heart contract and pump blood out to the lungs and the rest of the body. This contraction is crucial for maintaining blood circulation and ensuring that oxygenated blood reaches tissues and organs.

In contrast, diastole refers to the phase when the heart muscles relax and the chambers fill with blood. Depolarization and repolarization are terms that describe electrical changes in the heart during the cardiac cycle but are not directly the terms for contraction or relaxation. Depolarization occurs just before contraction as the heart's electrical system triggers the muscle fibers to contract, while repolarization happens as the heart muscle recovers after contraction. Understanding these phases is fundamental in grasping the overall function of the cardiovascular system.