Immunity

1. Immunity • Pathogens disease producing microbes (bacteria virus, fungi) • Immunity – body’s response to specific antigens (foreign proteins that invoke an immune response) Coordinated by T & B cells

2. Fig. 22.CO

3. Lymphatic Vessels • Lymphatic vessels – carry lymph, contain one way valves – very low pressure • Lymphatic capillaries blind pockets endothelial cells,prevent backflow into intercellular spaces • Thoracic duct drains lower abd. & pelvis, left half of head, neck & chest,empties into left subclavian & left jugular vein. • Right lymphatic duct – Drains Rt. side of body above diaphragm

4. Fig. 22.1

5. Lymph System • Lymph Fluid – moved by skeletal muscle pump and the respiratory pump 3.6L/day – eliminates local variations in the composition of interstitial fluid

6. Fig. 22.3a

7. Lymph System • Lymph Fluid – moved by skeletal muscle pump and the respiratory pump 3.6L/day – eliminates local variations in the composition of interstitial fluid • Lymphoid organs • Lymph nodes – “bean shaped” -collection sites filled with phagocytes • 99% of the antigens will be removed by lymph nodes

8. Fig. 22.6a

9. Lymph System • Lymph Fluid – moved by skeletal muscle pump and the respiratory pump 3.6L/day – eliminates local variations in the composition of interstitial fluid • Lymphoid organs • Lymph nodes – “bean shaped” -collection sites filled with phagocytes • 99% of the antigens will be removed by lymph nodes • Spleen – largest collection of lymphatic tissue(detects foreign substances), blood reservoir • Recycle center – macrophages engulf debris • Red pulp – remove abnormal or past prime RBC’s and recycle iron • White pulp – immune response - lymphoid nodules – microphages, stimulated by foreign antigens

10. Fig. pf 22.7abc

11. Lymph System • Thymus – max size by about age 1 decreases size in older adults • Site of T cell maturation –mature in the cortex, migrate to the medulla and enter blood vessels • thymic hormone production (thymosins)= maturation of T cells (cell-mediated immunity)

12. Fig. 22.8

13. Lymph System Functions • Drain excess interstitial fluid - 3.6L/day – eliminates local variations in the composition of interstitial fluid • 30L of fluid/day from capillaries →interstitial tissues • 27 L of fluid/day from interstitial tissues →capillaries • Transport dietary lipids - lacteals lymphatic vessels in small intestine • Carry out immune responses – destroy foreign invaders

14. Fig. 22.9

15. 7 Major Non-specific Defenses • Physical barriers - keep hazardous organisms and materials outside the body. • Phagocytes - cells that engulf pathogens and cell debris. • Immunological surveillance - the destruction of abnormal cells by NK cells in peripheral tissues • Interferons - are chemical messengers that coordinate the defenses against viral infection

16. 7 Major Non-specific Defenses • Complement - a system of circulating proteins that assist antibodies in the destruction of pathogens. • The inflammatory response - a local response to injury or infection that is directed at the tissue level. Mast cells come from basophils • Fever - an elevation in body temperature that accelerates tissue metabolism and defenses. • Denatures proteins • For each 1C rise in temperature, your metabolic rate jumps by 10 percent

17. Three Goals of Inflammation • The three goals of inflammation are: • To perform a temporary repair at the injury site and prevent the access of additional pathogens. • To slow the spread of pathogens away from the injury site. • To mobilize local, regional, and systemic defenses that can overcome the pathogens and facilitate permanent repairs. The repair process is called regeneration.

18. Specific Resistance • Immunity – response to a specific antigen’s molecular structure – occurs slowly- requires lymphocytes • Innate Immunity – Genetically determined • No prior exposure or antibody production involved • Acquired Immunity – Produced by prior exposure or antibody production

19. Fig. 22.25

20. Fig. 22.24

21. Fig. 22.13

22. Fig. 22.14

23. Cell vs Antibody Mediated Immunities • Cell-mediated immunity – coordinated by T cells. • Pathogens inside living cells - Viruses

24. Fig. 22.24

25. Cell vs Antibody Mediated Immunities • Cell-mediated immunity – coordinated by T cells. • Pathogens inside living cells - Viruses • Antibody-mediated immunity – Humoral immunity • B Cells • Antigens and pathogens in body fluids • Antibodies Y shaped

26. Fig. 22.24

27. Fig. 22.20abc

28. Fig. 22.20de

29. Immune Disorders • Autoimmune disorders – body mistakenly targets normal body cells and tissues, activated B cells manufacture antibodies against the cells • Rheumatoid arthritis • MS • Diabetes mellitus – insulin dependent • Thyroditisis

30. Fig. 22.a

31. Immune Disorders • Allergies – Foreign antigens – bacteria, viruses, pollen, dander, foods, drugs • Body creates an excessive response • Self antigens- molecules produced by the body = adaptive immune response • Allergens – antigens that trigger an allergic reaction

32. Immune Disorders • Aging : • ↓ helper T cell production = ↓ cell mediated immunity • ↓ primary and secondary antibody response • ↓ability to resist intracellular pathogens