Immunity Pathogens disease producing microbes bacteria virus fungi

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

Fig. 22. CO

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

Fig. 22. 1

Lymph System • Lymph Fluid – moved by skeletal muscle pump and the respiratory pump 3. 6 L/day – eliminates local variations in the composition of interstitial fluid

Fig. 22. 3 a

Lymph System • Lymph Fluid – moved by skeletal muscle pump and the respiratory pump 3. 6 L/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

Fig. 22. 6 a

Lymph System • Lymph Fluid – moved by skeletal muscle pump and the respiratory pump 3. 6 L/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

Fig. pf 22. 7 abc

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)

Fig. 22. 8

Lymph System Functions • Drain excess interstitial fluid - 3. 6 L/day – eliminates local variations in the composition of interstitial fluid – 30 L 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

Fig. 22. 9

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

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 1 C rise in temperature, your metabolic rate jumps by 10 percent

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.

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

Fig. 22. 25

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

Fig. 22. 24

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

Fig. 22. 24

Fig. 22. 20 abc

Fig. 22. 20 de

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

Fig. 22. a

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

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