When does diastole of the heart occur?

Diastole is the phase of the cardiac cycle during which the heart muscle relaxes after contraction. It is specifically characterized by the relaxation of the ventricles, allowing them to fill with blood coming from the atria. During this time, the atria are also filling with blood returning from the veins. The correct answer highlights this aspect of diastole: that it is the period when the atria are emptying into the resting ventricles, allowing for adequate filling before the next contraction occurs. This is crucial for maintaining efficient blood flow and proper heart function, as it ensures that the ventricles are adequately filled with blood, ready for the next systolic contraction to pump blood out to the lungs and the rest of the body. Understanding this process is vital for recognizing how the heart operates during its cycle and the importance of each phase, particularly diastole, in ensuring effective circulation.