Blood flow, also known as CIRCULATION, is the movement of blood through the body. It is a vital process that transports oxygen and nutrients to cells and carries away waste products. Blood flow is regulated by the heart, which pumps the blood throughout the body. The arteries carry oxygenated blood away from the heart, while the veins return deoxygenated blood back to the heart. Blood flow is essential for the functioning of all organs and tissues in the body.