During which phase does blood enter the arteries and artery walls stretch?

Systole is the phase of the cardiac cycle during which the heart contracts, pumping blood out of the ventricles and into the arteries. During this contraction, the pressure within the heart rises, causing blood to flow forcefully into the arteries. As a result, the artery walls stretch to accommodate the surge of blood. This increased pressure and volume during systole is what leads to the elastic expansion of the arterial walls. The arteries then help maintain blood pressure and ensure continuous blood flow to tissues during the diastolic phase, when the heart relaxes. The concept of systole is critical in understanding the dynamics of blood flow and pressure in the cardiovascular system.