How does a healthy heart function over the cardiac cycle?

A healthy heart functions through a coordinated cycle of contraction and relaxation known as the cardiac cycle, which consists of two main phases: systole and diastole. During systole, the heart muscles contract to pump blood out of the chambers—ventricles eject blood into the aorta and pulmonary arteries. In diastole, the heart relaxes, allowing the chambers to fill with blood from the atria and veins. This rhythmic sequence ensures efficient circulation, delivering oxygen and nutrients throughout the body while facilitating the removal of waste products.