The vascular system; composed of the heart (pump), distributed arteries, capillaries, and veins (vessels); is to maintain cellular homeostasis. Includes regulating cell development, absorption of essential nutrients (vitamins and minerals), and removal of cellular and metabolic waste products. Arteries and veins transport blood containing oxygen and essential nutrients.  Arteries carry oxygenated blood to the body, and veins carry blood from the body back to the heart. Capillaries, tiny vessels between arteries and veins, distribute blood to the body. The lymph vessels carry lymphatic fluid that filters fluid environment of the body. The system also plays keys roles in respiratory, digestive, urinary, and temperature control functions.