KINS 1224 Chapter 20: Chapter 20
Document Summary
Chapter 20: the circulatory system: blood vessels and circulation. The vessel wall: 3 categories of blood vessels, arteries. Carry blood away from heart: veins. Connect the smallest arteries to the smallest veins: walls of arteries and veins are composed of 3 layers called tunics, tunica interna. Regulates diameter of vessel: tunica externa. Loose connective tissue that merges with other vessels and organs. Provides passage for small nerves, lymphatic vessels, and smaller vessels. Small vessels called the vasa vasorum nourish the outer half of wall. Inner half is nourished by diffusion from blood in the lumen. Smaller branches that distribute blood to specific organs. Like exit ramps on a highway that lead to specific towns. 40 layers of smooth muscle constituting of wall thickness: resistance arteries. Sensory structures in their walls that monitor bp and chemistry. Transmit info to brainstem to regulate heartbeat, vessel diameters, and respiration. Occur in most tissues, such as skeletal muscle.
