BIOL 235 CHAPTER 21 BLOOD VESSELS HEMODYNAMICS EXAM TOPIC (QUESTIONS AND ANSWERS)

BIOL 235 CHAPTER 21 BLOOD VESSELS HEMODYNAMICS EXAM TOPIC (QUESTIONS AND ANSWERS) Hemodynamics - CORRECT ANSWER-the forces involved in circulating blood throughout the body Tunica Interna (Intima) - CORRECT ANSWER-inner lining of blood vessel and makes direct contact with blood Lumen - CORRECT ANSWER-Interior opening of the vessel Endothelium - CORRECT ANSWER-Innermost layer of tunica interna and is continuous with endocardial layer of the heart, consists of thin layer of flattened cells that are active participants in a variety of vessel-related activites basement membrane - CORRECT ANSWER-second component of tunica interna, lies deep to the endothelium. Provides physical support base for epithelial layer. Provides significant tensile strength but also resilience for stretching and recoil. Regulates molecular movement during tissue repair of blood vessel walls. Internal elastic lamina - CORRECT ANSWER-Outermost part of tunica interna and forms boundary between the turnica interna and tunica media. -Thin sheet of elastic fibers with windowlike openings (looks like swiss cheese) -Openings facilitate diffusion of materials between two layers Tunica Media - CORRECT ANSWER--muscular and connective tissue layer, displays greatest variation among different vessel types -most are a thin layer of smooth muscle cells with lots of elastic fibers -role regulate diameter of lumen Vasoconstriction - CORRECT ANSWER-increase in sympathetic stimulation causing the smooth muscle to contract decreasing the diameter of the lumen Vasodilation - CORRECT ANSWER-when smooth muscle fibers relax causing increase in diameter of the lumen External elastic lamina - CORRECT ANSWER-Separates tunica media from tunica externa, a network of elastic fibers. Tunica externa - CORRECT ANSWER--outer covering of blood vessels -consists of elastic and collagen fibers -contains nerves and tiny blood vessels that supply the tissue of the vessel wall Vasa vasorum - CORRECT ANSWER-small blood vessels that supply blood tot he tissues of the vessels Compliance - CORRECT ANSWER-usually high in arteries, their walls stretch easily or expands without tearing in response to a small increase in pressure Elastic arteries - CORRECT ANSWER-largest in body with largest diameter but their vessel walls are thin. Characterized by well-defined internal and external elastic laminae along with thick tunica media. Pressure reservoir - CORRECT ANSWER-How elastic arteries propel blood onward while the ventricles are relaxing. As blood ejected from the heart, their walls stretch and momentarily store mechanical energy, then the fibers recoil and convert stored energy in the vessel into kinetic energy of the blood. muscular arteries - CORRECT ANSWER--medium sized arteries -tunica media contains more smooth muscle and less elastic fibers -walls are relatively thick and are capable of greater vasoconstriction and vasodilation -well defined internal elastic lamina, thin external elastic lamina -tunica externa thicker than tunica media and contains fibroblasts, collagen fibers and elastic fibers preventing shortening when fiber is cut -no ability to recoil, contracts and maintains partial contraction (muscular tone)