Waste products are taken up by the capillaries at their venous end. There are three major types of blood vessels: the arteries, which carry blood away from the heart, the capillaries, which enables the exchange of water and chemicals between the blood and the tissues and the veins, which carry blood away from the capillaries to the heart. Blood capillaries functions by carrying the necessary nutrients to the body cells and carrying away the waste products from the cells.