What does diastole refer to in the cardiac cycle?

Diastole refers specifically to the phase in the cardiac cycle when the heart muscle relaxes. During this period, the chambers of the heart, including the atria and ventricles, fill with blood. This relaxation is essential for allowing adequate blood flow into the heart and subsequently for optimal circulation throughout the body.

The importance of diastole cannot be overstated, as it is during this phase that the coronary arteries also receive blood supply, nourishing the cardiac muscle itself. Understanding diastole is crucial for grasping the overall dynamics of the cardiac cycle, which alternates between contraction and relaxation phases to maintain effective blood circulation.