Arteries and veins

are important components of the circulatory system. Arteries carry oxygenated blood away from the heart and towards the body’s cells and organs. Veins carry deoxygenated blood back to the heart. The walls of the arteries and veins contain smooth muscle that helps regulate the flow of blood. The walls of the capillaries are very thin and allow oxygen and nutrients to pass through into the body’s cells and tissues.