1. Immunology PhagocytesKiller T-cells Macrophages Natural Killer Cells

2. Immune System Group of cells in the body that recognize foreign substances F(x) = to neutralize or destroy all things “non-self” (pathogens or invaders)

3. What is a Pathogen? Any toxin, living organism, or other agent that can cause disease.

4. Immune Cells Immune cells circulate throughout the body in the blood system and the lymphatic system

5. Lymphatic System A network of vessels that penetrate nearly every tissue of the body, and a collection of tissues & organs that produce immune cells F(x):  Fluid recovery from tissues Lymph = fluid  Immunity Lymph is filtered before returning to blood

6. Lymph Tissues & Organs Lymph Nodes  Clean the lymph & alert the immune system to pathogens Tonsils  Guard against ingested or inhaled pathogens Thymus  Produces T-cells Spleen (largest Lymph Organ)  Monitors blood for foreign objects  Recycles old RBCs TONSIL

7. Body Defense - Two Types 1. Non-Specific 2. Specific

8. Non-Specific Body Defense Innate or inborn, not affected by prior exposures NOT specific for any invader Operates constantly

9. Non-Specific Body Defense SKIN – 1 st Line of Defense  Physical barrier = prevents entry of pathogens  Must be unbroken to be effective  Acidic, oily, sweat glands– inhibits bacterial growth

10. Non-Specific Body Defense MUCUS MEMBRANES  Respiratory, Digestive, Urinary, Reproduction tracts  F(x): To trap debris & pathogens

11. Non-Specific Body Defense HAIRS  Nasal passage  Traps debris & pathogens CILIA  Upper Respiratory Tract  Traps debris & pathogens

12. Non-Specific Body Defense CELLULAR DEFENSE  Activated when other defenses are breached  Two Types: Phagocytes Leukocytes Phagocyte eating dying cells.

13. Phagocytes Cell’s that recognize “non-self” items F(x): engulf or “eat” foreign debris Reside in lymph organs Travel to the site of infection, via the blood stream  Macrophage – a type of phagocyte

15. Leukocytes (Natural Killer Cells) a.k.a. NK Cells WBCs police the blood & lymph F(x):  Bind to membrane of the invader, release chemicals, cause infected cell to lyse

16. Non-Specific Body Defense CELLULAR (TISSUE) DEFENSE  Inflammatory Response  Fever

17. Inflammation Local defensive response to tissue injury of any kind Response is directly at site of injury Helps to prevent spread of the damaging agent

18. Inflammation The 4 Signs of Inflammation – S.H.A.R.P.  Swelling  Heat ↑  All four of these – due to fluid build-up ↓  Redness  Pain

21. Fever Abnormal elevation in body temp.  Response to infection Stimulates phagocytes to go to work Heat kills many pathogens Increases the rate of enzymatic rxns

22. Non-Specific Body Defense CHEMICAL DEFENSE  Interferons (antiviral proteins)

23. Interferons Secreted by virus-infected cell Stimulates non-infected cells to make proteins that block viral protein synthesis Slows infection to allow specific defenses to begin working Activates macrophages to “eat” (non-self) viral invaders

24. Specific Body Defense Immunity = ability to ward off a specific infection or disease  Highly specific resistance to disease Process:  Particular invader recognized  Switches on immune response  Invader is remembered so that future invasions can be immediately fought

25. Specific Body Defense Specific Body Defense is born out of the Lymphatic System  i.e. Bone marrow  makes B-cells, which make specific antibodies

26. Antigens Irritant or pathogen– molecule that react with antibodies  Epitope = region of antigen recognized by a specific antibody Stimulates formation of antibodies

27. Antibodies Molecules that react with or bind to antigens  Mark antigens for destruction by macrophages Form due to the exposure to a specific antigen

28. Antibodies Made by B-cells Found in plasma, & all body secretions Once present, allows immediate immune response to pathogens

29. Antibodies Structure (most common)  Composed of 2 heavy chains, 2 light chains  Constant & Variable regions  Antigen-binding site Variable region Constant region

30. Specific Body Defense Helper T-cells  Attract other T-cells (Killer T-cells) and macrophages to an antigen Killer T-cells  Directly attack & kill pathogens, release chemicals to lyse cells

31. Specific Body Defense Suppressor T-cells  Stops immune response when antigen is successfully overcome Scanning Electron Micrograph of a T-cell

32. Specific & Non-specific Defenses work together to protect the body from disease-producing pathogens B-cells mature in bone tissue T-cells mature in thymus tissue

33. Applications of Immune Response Immunization= process that increases an organism’s rxn to antigen & therefore improves its ability to resist or overcome infection. Vaccine= living or inactivated organism used to induce specific immunity

34. Vaccines Attenuated agents:  Virus/bacteria that has been modified to be incapable of causing disease Inactivated agents:  Pieces or a whole organism that has been chemically inactivated  Can’t reproduce but retains antigenicity

35. Immunity 3 Types:  Active  Passive  Cell Mediated

36. Active Immunity When an individual responds to an antigen  Resulting from vaccination against or  Recovery from a natural infection Permanent Immunity

37. Passive Immunity Antibodies produced from another organism injected into the body Temporary protection against disease

38. Cell-Mediated Immunity Killer T-cells attack any cell not marked with a special protein (i.e. cells that are “non-self”)