KIN 272 Chapter Notes - Chapter 19: Tunica Intima, Tunica Externa, Tunica Media
Document Summary
Blood is transported throughout the body via a continuous system of blood vessels. Arteries transport blood away from the heart. Veins carry blood back to the heart. Capillaries carry blood tissue cells and are exchange sites. 19. 1 most blood vessel walls have three layers. All blood vessels except capillaries have three layers: tunica intima, tunica media, and tunica externa. Capillary walls are composed of the tunica intima only. 19. 2 arteries are pressure reservoirs, distributing vessels, or resistance vessels. Elastic (conducting) arteries are the large arteries close to the heart that expand during systole, acting as pressure reservoirs, and then recoil during diastole to keep blood moving. Muscular (distributing) arteries carry blood to specific organs. They are less stretchy and more active in vasoconstriction. Arterioles regulate blood flow into capillary beds. Atherosclerosis is a degenerative vascular disease that decreases the elasticity of arteries. Capillaries are microscopic vessels with very thin walls.
