1. What Causes Disease? Germ Theory of Disease: –Developed by Louis Pasteur and Robert Koch Infectious diseases occur when microorganisms cause changes that disrupt normal body functions

2. Pathogens: –disease producing agents that are foreign to the host –Ex: Bacteria, protozoa, fungi, viruses, microbes What Causes Infectious Disease?

3. How are Diseases Transmitted? Direct contact/exchange of bodily fluids: –kissing, sexual intercourse Contact with Object: –contaminated surfaces, needles Air-bourne: –sneezing, coughing Contaminated Water or Food Animal Vector: (carries disease but is not sick) –Ex: mosquitos (malaria) fleas (plague), ticks (lyme disease)

4. Flu Attack: How a virus invades your body http://www.youtube.com/watch?v=Rpj0em EGShQ&safe=activehttp://www.youtube.com/watch?v=Rpj0em EGShQ&safe=active

5. Defense Against Infection Physical and Chemical Barriers: –Skin –Saliva, mucous and tears all contain lysosome, an enzyme that breaks down bacterial walls –Stomach acids –Cilia

6. Defense Against Infection Inflammatory response –Antigens trigger release of histamines from certain cells –Histamines increase blood flow to the infected area bringing more WBCs –Area gets hot, red and painful Fever: –chemicals are released that increase body temp which can stop or slow growth of some pathogens and can speed up immune response

7. The Immune Response Function of the transport system Reaction of body to foreign organism or substances not normally present in the body (antigens)

8. Specific Defenses Body must distinguish between “self” and “non- self” and inactivate or kill any foreign substance or cell that enters the body Immune defenses are triggered by antigens typically located on the outer surface of bacteria, viruses or parasites Responds by increasing the number of cells that attack invaders or produce antibodies.

9. Antibodies –“tag” antigens for destruction by immune cells May be attached to certain WBC May be free floating in blood plasma –The shape of each type of antibody allows it to bind to one specific antigen

10. The Role of WBCs Phagocytic WBC: ingest and destroy pathogens –Called macrophages, they engulf and destroy cells and bacteria Lymphocytes: –WBCs that produce specific antibodies that neutralize antigens http://www.youtube.com/watch?v=lrYlZJiuf18&list=PL2165FA6A0E3DDF85&safe=active

11. Bacteria invade and are engulfed by macrophages Macrophage takes portion of bacteria and positions it in its cell membrane as antigens Special WBC called helper T-cells bind to these antigens and become ‘activated” The T-cells then bind to B-cells causing them to divide and produce plasma cells and memory B cells Plasma cells secrete antibodies Memory B cells and antibodies stay in the bloodstream and attack and mark the antigens quickly for destruction by macrophages the next time they enter the body Antibodies recognize the antigens to which it should bind Form an antibody-antigen complex http://www.youtube.com/watch?v=Ys_V6FcYD5I&list=PL2165FA6A0 E3DDF85&safe=activehttp://www.youtube.com/watch?v=Ys_V6FcYD5I&list=PL2165FA6A0 E3DDF85&safe=active Immune Response (Read Only)

12. Fighting Infectious Disease Active Immunity –From natural exposure to antigen fighting an infection –From deliberate exposure to antigen vaccination

13. How does Active Immunity Work? –You are exposed to an antigen –Body actively creates antibodies to fight it –WBCs recognize foreign substance (antigen) and develop specific antibodies to it –Immunity lasts a long time

14. Why Don’t I Get Chicken Pox Twice? –Once you fight off an infection, your body produces “memory cells” –These cells stick around in blood and react quickly if exposure to that particular antigen happens again –Person won’t develop the full blown disease again

15. What happens when you get Vaccinated?

16. Smallpox and Vaccine Development Jenner, Smallpox and the Development of the First Vaccine: http://www.youtube.com/watch?v=qdrpujS HfsU&safe=active

17. What is in a vaccine? Dead or weakened version of the pathogen. –Not enough to cause a full blown disease Stimulates lymphocytes to develops antibodies specific to that antigen Vaccines: http://www.youtube.com/watch?v=A 9HUN5kKK4A&safe=active

18. “Memory” cells remember this antigen so antibodies can be produced quickly next time you are infected If ever exposed to antigen in the future your body will be able to fight it off quickly Helps develop “active” immunity

19. How Vaccines Work http://www.youtube.com/watch?v=k3CW xekGt7Y&safe=activehttp://www.youtube.com/watch?v=k3CW xekGt7Y&safe=active

20. Why do I have to get a Flu Shot every year? –There are many variants of the virus that causes Flu Antibodies are specific to only one antigen –Virus can undergo mutations that make it resistant to certain antibodies that might have been effective in the past The Flu Shot: http://www.youtube.com/watch?v=5q8RNbeJTmI&safe=active

21. Passive Immunity –Person given antibodies they don’t make themselves –They are not exposed directly to the antigen –Immunity lasts only a short time –Ex: Passed from pregnant woman to fetus (across placenta) or to baby through breast milk Injected directly (ex: antibodies for rabies)

22. Immune System Disorders Allergies –Body responds to a harmless antigen (like pollen, peanuts) –Often produces an elevated inflammatory response. –Not everyone has the same sensitivity to the antigen Autoimmune Diseases –Bodies immune system attacks your own cells

23. AIDS –AIDS is caused by the human immunodeficiency virus (HIV). –This virus weakens the immune system and the person is unable to fight off infections T cells involved in immune response get killed.

24. –Victim vulnerable to many serious diseases, such as tuberculosis, pneumonia, fungal infections, and cancer. –Death usually occurs as a result of one of these diseases.

25. AIDS—Modes of Infection (read only) –having unprotected sex with a person who is infected –sharing a needle (shooting drugs) with a person who is infected –being born from or drinking the breast milk of a woman who is infected. Some people were infected with HIV from getting a blood transfusion from an infected person. Today, the blood supply is carefully tested, and risk of infection from a blood transfusion is very low.

26. Organ Transplants If a person wanted to get an organ transplant from another person why might this be a problem? Why might they need to take immuno- suppresent drugs? Why might these drugs be dangerous to take?

27. Some Extra Online Videos for Review Crash Course: Circulatory Overview http://www.youtube.com/watch?v=9fxm85 Fy4sQ&safe=activehttp://www.youtube.com/watch?v=9fxm85 Fy4sQ&safe=active Bill Nye: Blood and Circulation Review: http://www.youtube.com/watch?v=WqiPBg VbFDU&safe=activehttp://www.youtube.com/watch?v=WqiPBg VbFDU&safe=active