chap14outline - Chapter 14 - Lymphatic System and Immunity...

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Chapter 14 - Lymphatic System and Immunity 14.1 Introduction (p. 384; Fig. 14.1) A. The lymphatic system is comprised of a network of vessels that circulate body fluids. B. Lymphatic vessels called lacteals transport fats to the circulatory system. C. The organs of the lymphatic system help defend against disease. 14.2 Lymphatic Pathways (p. 384) A. Lymphatic pathways start as lymphatic capillaries that merge to form larger vessels that empty into the circulatory system. B. Lymphatic Capillaries (p. 384; Fig. 14.2) 1. Lymphatic capillaries are tiny, closed-ended tubes that extend into interstitial spaces. 2. They receive tissue fluid through their thin walls; once inside, tissue fluid is called lymph. C. Lymphatic Vessels (p. 384; Fig. 14.3) 1. The walls of lymphatic vessels are thinner than those of veins but are constructed with the same three layers with semilunar valves on the inside. 2. Larger lymphatic vessels pass through lymph nodes and merge to form lymphatic trunks. D. Lymphatic Trunks and Collecting Ducts (p. 384; Figs. 14.4-14.5) 1. The lymphatic trunks drain lymph from the body and are named for the regions they drain. 2. These trunks join one of two collecting ducts---either the thoracic duct or right lymphatic duct. 3. The thoracic duct drains into the left subclavian vein, while the right lymphatic duct drains into the right subclavian vein. 14.3 Tissue Fluid and Lymph (p. 386) A. Tissue fluid becomes lymph once it has entered a lymphatic capillary; lymph formation depends on tissue fluid formation. B. Tissue Fluid Formation (p. 386) 1. Tissue fluid is made up of water and dissolved substances that leave blood capillaries by filtration and diffusion. 2. During filtration, some smaller proteins leak from capillaries into the tissues and are not returned to the bloodstream, thus increasing osmotic pressure within the tissues. C. Lymph Formation and Function (p. 386) 1. Rising osmotic pressure in tissues interferes with the return of fluids to the bloodstream. 2. Increasing interstitial pressure forces some of the fluid into lymphatic capillaries. 14.4 Lymph Movement (p. 386) A. The hydrostatic pressure of tissue fluid drives the entry of lymph into lymphatic capillaries. B. Forces that move blood in veins (skeletal muscle contraction, breathing movements, and contraction of smooth muscle in the walls of lymphatic trunks) are the forces that propel lymph through lymphatic vessels. C. A condition that interferes with the flow in lymph will result in edema. D. During surgery, lymphatic vessels or tissues may be removed or disturbed, resulting in edema.
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14.5 Lymph Nodes (p. 387) A. Lymph nodes, which contain lymphocytes and macrophages, are located along lymphatic pathways. B.
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This note was uploaded on 05/20/2010 for the course PHYSIOLOGY Physiology taught by Professor Holes during the Spring '10 term at Open Uni..

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chap14outline - Chapter 14 - Lymphatic System and Immunity...

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