1. Biology 322 Human Anatomy Dr. Thompson Lymphatics

2. Lymphatic System Functions 1) Provide alternate pathway for extracellular fluids to return to circulation. 2) Provide pathways for waste materials to be removed from tissues and organs and destroyed. 3) Provide a protective lining along internal organs which are exposed to the environment. 4) Provide places for surveillance, proliferation and maturation of lymphocytes and other immune cells

3. Lymphatic System Two interrelated components: 1) 2)Lymphatic Lymphatic tissues Lymphatic cells

4. Lymphatic vessels: Microscopic

5. Lymphatic vessels: Macroscopic / Gross

6. Concentrated

9. Other Lymphatic Organs and Tissues Spleen, Thymus Tonsils, Appendix, Lymphatic tissue lining

10. Spleen Inferior to diaphragm on left side of abdomen Large blood supply through splenic artery (branch of from ) Two types of tissue: a) Red pulp produces reservoir for

11. Spleen Inferior to diaphragm on left side of abdomen Large blood supply through splenic artery (branch of celiac trunk from aorta) Two types of tissue: b) White pulp contains

12. Thymus Superior thorac, anterior to aorta & posterior to sternum Large in children, involutes in adults

13. Lymphoid tissues ( ) line many hollow organs exposed to bacteria, viruses, etc Clusters, called lymphatic nodules, Located just deep to epithelia, easily exposed to antigens Secrete antibodies into and across epithelia into lumen Often located near "pits" or "crypts" where bacteria, viruses, & other contaminants can be trapped

14. Lymphoid tissues (lymphocytes and macrophages) line many hollow organs exposed to bacteria, viruses, etc Some nodules given special names: