1. Ch 31 – Section 1 Immune system Protect body from pathogens ANY FOREIGN PROTEIN = antigens Examples  Bacteria  Viruses  Fungi  Protozoa (animal-like protists)  Parasites Vector = anything that carries a pathogen into healthy cells

2. Lymphoid organs Lymph nodes Thymus gland Filter/purify lymph before returning it to blood 99% of antigens removed Antigens engulfed by macrophages and ‘presented’ to lymphocytes Under sternum Throughout body ‘home’ of lymphocytes (T cells) Secretes thymosin to stimulate T cell differentiation Reduction in size with age

3. Lymphoid organs Spleen Tonsils Removes abnormal blood cells Stores./recycles Fe from RBCs Initiates T cell and B cell response Large nodules in pharynx

5. Ch 31 – Section 3 Immune system Nonspecific defenses Specific responses  Physical barriers (1 st line of defense)  Phagocytes  NK cells  Interferon  Complement  Inflammation  Fever Immune response = immunity Cell mediated immunity = T cells Antibody mediated immunity = B cells

6. Nonspecific defenses Physical barriers (1 st Line of Defense) White Blood Cells (2 nd Line of Defense) Phagocytes Integumentary system Skin, Hair, Sweat Mucous secretions from all epithelial linings Cells that may engulf, bind/remove, release toxins against antigens

7. Nonspecific defenses NK cells Interferon Complement Natural killer cells Kill any cell with ‘abnormal’ proteins Stick to ‘bad’ cell and secrete proteins that disintegrate its cell membrane Attack virus infected and cancer cells Small proteins released infected cells to ‘warn’ healthy cells of presence of pathogens which allows healthy cells to protect themselves from destruction 11 complement proteins Stimulated by Attachment of antibodies to target cell membrane attachment of pathogens to cell wall/membrane

8. Nonspecific defenses Inflammation Acute inflammatory response = immediate response to injury *1 Release of histamines = increased blood flow to area *2 Clotting mechanisms cascade to isolate area and stop bleeding *3 Local temperature rises = increased enzyme activity and denaturing of pathogen proteins *4 Neutrophils called to area Phagocytize pathogens release toxins in area Secrete cytokines to call other phagocytes to area

9. Nonspecific defenses Inflammation (continued) *5 Macrophages and eosinophils called to area increase activity *6 more cytokines released stimulating fibroblasts to produce scar tissue *7 activity stimulates neural response as sense of pain causing organism to respond *8 specific responses initiated (cell mediated immunity) foreign invaders ‘presented’

10. Nonspecific defenses Fever Pyrogenes stimulate hypothalamus to increase body temperature Increased temperature = increased enzyme activity and denaturing of pathogen proteins, stimulate White Blood Cells

11. Specific response Immune response = immunity Immunity may be: Innate = Acquired = Born with it As a result of exposure to antigen or Vaccine

12. Ch 31 – Section 2 Immunity Specific Versatile Memory Tolerance Response is specific to antigen encountered Can respond to any antigen at any time Memory cells remember response to initial contact with antigen Ignores ‘self’ antigens

13. Immunity Immunity is a result of coordinated activities of lymphocytes Lymphocytes T cells B Cell mediated immunity Antibody mediated immunity

14. T cells and cell mediated immunity T cells activated by exposure to antigen TC TC cells Memory TC TC cells TH TH Memory TH TH cells TS TS T cytotoxic cells Physically and chemically attack antigens naturally on cell surface Remember antigen for future encounter T helper cells stimulate B cell activity stimulate NK cell activity Remember antigens for future encounter T suppressor cells Inhibit T cell and B cell activity

15. B cells and antibody mediated immunity Produce antibodies to antigens on cell surface B cells activated by T H cells B cells ‘sensitized’ when encountering specific antigen When activated T H cell encounters sensitized B cell: B cells stimulated to produce memory cells ORbecome plasma cells Plasma cells produce antibodies specific to antigen

16. Antibody–Antigen complex Antigen Eliminated by: Neutralization Agglutination/ precipitation Activation of complement Attract phagocytes Assist phagocytes in phagocytosis Stimulate inflammation Prevent entrance of pathogens in mucous membranes Prevent pathogen from attacking host cell Large numbers of antigens ‘clump‘ together causing precipitation Primary responseSecondary response Initial exposure to antigen Longer response Subsequent exposure to antigen Memory cells = quicker response

17. Immune Hormones Interluekins Interferon Stimulate T cells and B cells Enhance nonspecific defenses Make cells and neighbors resistant to viral infection Stimulate NK cells

18. Ch 31 – Sections 5 & 6 Immune disorders Autoimmune disease ‘self’ is not recognized Immunodeficiency Viral (HIV) – virus that attacks the immune system by infecting T cells Leukemia – cancer of the bone marrow causes abnormal WBC Allergies Inappropriate immune response (to nonpathogenic antigen) Primary response to allergen not severe secondary response = allergic reaction Anaphylaxis = acute allergic response to allergen