These arteries distend when the blood pressure rises during systole and recoil when the blood pressure falls during diastole.

The cardiac impulse is the result of the heart rotating, moving forward and striking against the chest wall during systole.

This period occurs in the ascending phase of the T wave, when the ventricular myocardium is repolarizing, moving from systole to diastole (relaxation).

It can be more readily used by cells to contract muscles or to generate nerve impulses or do whatever else grow, or divide, or whatever else the cell might need.