What does systole represent in the cardiac cycle?

Systole refers to the phase of the cardiac cycle during which the heart chambers contract. This is a crucial part of the heart's functioning because it is during systole that blood is pumped out of the heart and into the arteries, ensuring the circulation of blood throughout the body. Specifically, during ventricular systole, the ventricles contract, leading to the ejection of blood into the aorta and pulmonary artery.

This contraction is vital for maintaining adequate blood pressure and ensuring that oxygenated blood reaches the tissues and organs. The contraction phase is integral to the heart’s overall efficiency and effectiveness in delivering blood.

Other options may refer to different aspects of cardiac function, such as diastole, which is the relaxation phase when the heart fills with blood, or the rate of heartbeats, known as the heart rate. However, these do not accurately describe what systole represents in the cardiac cycle.