Step-by-step explanation:
After blood has left the heart, the heart muscle must contract in order to push blood into the chambers and fill them again. This process is called systole, and it helps to maintain the flow of blood throughout the circulatory system. When the heart muscle relaxes, it allows the chambers to fill with blood again, which is called diastole. This cycle of contraction and relaxation enables the heart to efficiently pump blood to the rest of the body.