Doncouse_Jeremy_Week4-5

Doncouse_Jeremy_Week4-5 - Running head: CHAPTER 19 1 Week...

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Running head: CHAPTER 19 1 Week 4-5 Written Assignment Jeremy Doncouse Mountain State University
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CHAPTER 19 Chapter 19: The Cardiovascular System: Blood Vessels PART 1: OVERVIEW OF BLOOD VESSEL STRUCTURE AND FUNCTION 1. Describe the three layers that typically form the wall of a blood vessel, and state the function of each. The lumen is the empty space inside the blood vessel. The tunica interna is the innermost layer of endothelium, made of simple squamous epithelium (slick). The tunica media is the middle layer of circular smooth muscle and sheets of elastin, innervated by vasomotor nerve fibers of sympathetic division of ANS. The tunica externa (adventitia) are collagen fibers with nerve fibers, lymph vessels, some elastin, and blood vessels. 2. Define vasoconstriction and vasodilation. Vasoconstriction is contraction of smooth muscle to decrease diameter of lumen. Vasodilation is relaxation of smooth muscle layer to increase diameter of lumen 3. Describe the structure and function of a capillary bed. Capillary beds are microcirculatory networks consisting of a vascular shunt and true capillaries, which function as the exchange vessels between an arteriole and venule. 4. Describe the structure and function of veins, and explain how veins differ from arteries. Vein’s walls are thinner and have larger lumen, but they do possess all three tunics as in arteries. Tunica media contains little smooth muscle and externa is thickest. 65% of blood in body is found in veins at any one time (blood reservoir). Venous valves prevent backflow of blood and are formed from folds of tunica interna. Most valves in veins of limbs. Varicose veins are tortuous (twisty) and dilated due to incompetent valves; gravity and pressure affect them. Anastomoses connect veins together, artery together, or arteries to veins.
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Running head: CHAPTER 19 3 PART 2: PHYSIOLOGY OF CIRCULATION 1. List and explain the factors that influence blood pressure, and describe how blood pressure is regulated. The pumping action of the heart generates blood flow; pressure results when blood flow
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Doncouse_Jeremy_Week4-5 - Running head: CHAPTER 19 1 Week...

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