Lymphatic System

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Chapter 16-Lymphatic System & Immunity

1. Explain the functions of the lymphatic system.

The lymphatic system functions to balance fluid, lipid absorption (via lacteals=lymph capillaries) and defense. It removes toxins/pathogens, fight infections and transports excess fluid in the interstitial spaces and returns it to the blood stream. Lacteals absorb digested fats from small intestines and transports it to venous circulation.

2. Trace the general pathway of lymph from the interstitial spaces to the bloodstream.

Lymphatic capillaries are found near the systemic and pulmonary capillary networks. From there it moves through lymph vessels into the lymph nodes. Then it returns to the lymph vessels and returns to the blood stream in difference places.

3. Distinguish between tissue fluid and lymph.

Lymph is tissue fluid that has entered into a lymphatic capillary.

4. Describe the primary functions of lymph.

Lymph transports foreign material and bacteria to the lymph nodes and returns protein to the blood that has leaked out of the capillaries.

5. Explain why physical exercise promotes lymphatic circulation.

The lymphatic circulation relies on contractions of skeletal muscles, breathing, and smooth muscles of the lymphatic trunks, which all assist in moving lymph through the body.

6. Explain how a lymphatic obstruction leads to edema.

Lymphatic System is always moving fluid through so the volume remains stable but if a blockage or obstruction occurs the fluid will back up and cause edema. An example is if a lymph node is removed due to cancer then the area may not drain properly causing edema.

7. Sketch a lymph node, and label its parts.

8. Describe the major body regions containing lymph nodes. The major body regions are the axillary region, inguinal region, the pelvic cavity, the abdominal cavity, the cervical region, the thoracic cavity, and the supratrochlear region.

9. Explain the functions of a lymph node. Lymph nodes are made of fibrous connective tissue divided into compartments that contain dense masses of macrophages and lymphocytes. The masses are called nodules & nodules make up lymph nodes. Lymph nodes function to produce lymphocytes, to carry out phagocytosis of foreign substances, cell debris, and damaged cells.

10. Indicate the locations of the thymus and spleen. The thymus is in the mediastinum anterior to the aortic arch and posterior to the upper part of the body of the sternum and extends from the root of the neck to the pericardium. The spleen is located in the upper left portion of the abdominal cavity just inferior to the diaphragm posterior and lateral to the stomach and reference plates 4, 5, and 6.

11. Compare and contrast the functions of the thymus and spleen.

The thymus functions to produce T-lymphocytes that assist in immune response. It also secretes thymosin that is believed to stimulate the T-lymphocytes to mature after they leave the thymus. The spleen functions to filter blood and stores extra red blood cells in the venous sinuses and stores large number of lymphocytes in its nodules.

12. Defense mechanisms that prevent the entry of many types of pathogens and destroy them if they enter provide innate, (nonspecific) defense. Mechanisms that are very precise, targeting specific pathogens provide adaptive (specific) defense. Nonspecific body defenses: species resistance, mechanical barriers (skin and mucous membranes), and chemical barriers (enzymes, interferon), inflammation, and phagocytosis. Specific body defenses: Immune mechanisms, Lymphocytes and macrophages recognize foreign substances and take action to remove them.

13. Define species resistance. Some species are resistant to certain pathogens/diseases because their tissues do not either have the right environment (chemically), they lack the tissue type/target cell for the bacteria to attach to, or they lack the right temperature for the disease to grow. For...
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