The function of the arteries is to carry oxygenated blood to organs and cells in the body. Because of this, arterial blood has a bright red color and flows away from the heart.
Arterial walls have three layers. The outer layer is elastic connective tissue, and the middle layer is made out of muscle. The inner lining of the artery is made up of smooth cells called the endothelium, which are similar to the cells in the heart. When the heart beats, the walls of the arteries enlarge to make room for the blood that's pumped into them. Then, the muscular layer contracts slowly to pump the blood further down the arteries to the arterioles and capillaries.
