What term describes the contraction of the heart, especially that of the ventricles?

The term that describes the contraction of the heart, particularly the ventricles, is systole. During systole, the ventricles contract to pump blood out of the heart and into the arteries—specifically, the right ventricle sends blood to the lungs for oxygenation via the pulmonary artery, and the left ventricle pumps oxygenated blood to the rest of the body through the aorta. This contraction is a vital part of the cardiac cycle, allowing the circulation of blood, which is essential for delivering oxygen and nutrients to tissues while also removing metabolic waste.

In contrast, diastole refers to the phase when the heart muscle relaxes, allowing the chambers to fill with blood. Cardiac arrest is a critical condition in which the heart stops beating effectively, leading to a cessation of blood flow. Atrial contraction is a part of the cardiac cycle as well, occurring before ventricular contraction, but it does not describe the contraction of the ventricles themselves. Understanding these phases and terms is key to comprehending how the heart functions in pumping blood throughout the body.