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Teacher Notes

Teacher Notes. This PPT was revised February 20, 2006.

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Teacher Notes

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  1. Teacher Notes • This PPT was revised February 20, 2006. • The PPT contains a video clip from the Prentice Hall Biology book, Chapter 40A.mpg. In order for it to play, you must have the video clip where it can be found by the PPT. It should play from the Database. If you put the PPT on your C drive you must relink the video. The video is found on the Prentice Hall CD.

  2. Defense Against Disease Pathogens, Disease and The Immune Response Photo of HIV lysing Helper T cellPhotograph, Mushin Ozel, Robert Koch-Institute

  3. What are the basics? • Homeostasis is the ability of an organism to maintain a stable internal environment. • Diseases can disrupt this stability. • Your immune system is the organ system that protects your body from disease. (housed in the lymphatic system) • Your body has three different lines of defense against pathogens, or disease causing agents.

  4. How does the circulatory system work with the immune system? • Circulatory system: a network of veins, arteries and blood vessels that transports blood to and from the heart. • The circulatory system helps to fight the infection by transporting the immune system’s specialized cells to the source of the infection.

  5. Pathogens: The Culprits • Can be a protist • Can be a virus • Can be a bacterium Examples of autoimmune diseases: Type I diabetes, multiple sclerosis • Can be YOUR OWN CELLS! When this occurs, it is called an autoimmune disorder. Examples of protist diseases: malaria, amoebic dysentery Examples of bacterial diseases: strep throat, botulism, salmonella Examples of viral diseases: cold, flu, HIV

  6. Transmission Methods(How did that pathogen get to me?) • PHYSICAL CONTACT – directly touching a person who is infected, sexual contact or coming into contact with infected body fluids (blood or even droplets in the air from a sneeze) • CONTAMINATED FOOD OR WATER – food poisoning, uncooked meat, water contaminated because of poor sanitation • INFECTED ANIMALS – bites from infected animals (ticks, fleas, mosquitoes, rabid dog)

  7. IMMUNE SYSTEM • The immune system is the body’s system of defense to stay healthy. • The function of the immune system is to fight infection through the production of cells that inactivate foreign substances or cells.

  8. What are the two types of immune defense? The immune system includes two general categories of defense mechanisms against infection. • Nonspecific defenses guard against infections by keeping most things out of the body. • Specific defenses track down specific pathogens.

  9. Anatomical Barriers The First Line of Defense • The first line of defense is NONSPECIFIC - they do not discriminate between one threat and another. Eyes (tears) Nose (cilia & mucus) Mouth (saliva) A. SKIN - prevents entry of most pathogens if unbroken B. CILIA - tiny hair-like structures that trap and push pathogens out, in nose & respiratory tract Lungs (mucus) C. MUCUS - thick liquid that traps pathogens and aids in removal Skin (barrier) D. LYSOZYMES - enzymes in saliva, sweat, tears and mucus that break down cell walls of bacteria. E. ACID ENVIRONMENT - acid in stomach and skin surface (pH of 3-5) too acidic for most pathogens Stomach (digestive acids)

  10. Eyes (tears) Mouth (saliva) Lungs (mucus) Skin (barrier) Stomach (digestive acids) Anatomical Barriers The First Line of Defense • Identify the body defense that would be most active in these situations. A. You inhale a microbe that can produce tuberculosis. B. A staph bacterium makes contact with your exposed skin. C. You eat a sandwich in which the meat has spoiled. D. A speck of dust covered with bacteria gets in your eye. E. Some medications cannot be given orally or on the skin. Instead they must be injected directly into the muscle or bloodstream. Why?

  11. White blood cells move from the vessels to enter the infected tissues. White blood cells engulf and destroy pathogen. Blood vessels near the wound expand. Injury occurs allowing pathogens to enter the body. Inflammatory ResponseSecond Line of Defense • Inflammatory response is a nonspecific defense reaction to tissue damage caused by injury or infection.

  12. Inflammatory Response • Pick out the five indicators of inflammation from this video. inflammatory response Prentice Hall Biology. Ch 40 A

  13. Inflammatory Response • Key Defenses: • Phagocytes: wbc that engulf and destroy pathogens • Fever: increase of body temperature to slow down or destroy pathogens • In the case of Viral Infection: • Interferon: protein produced by viral infected cells to help other cells resist infection

  14. Helper T cells macrophages B cells Killer T cells antibodies B-memory cells Third Line of Defense: The Immune Response The immune response is a SPECIFIC DEFENSE - the body defenders are specific to attack only a particular disease-causing agent. The substance that triggers the response is known as an antigen.

  15. They recognize and consume pathogens by phagocytosis. After consuming the invader, they can display to other cells that an intruder is present. Macrophage: “big eater” Usually first cells on the scene where they identify the foreign invader. Macrophages

  16. Helper T cells Killer T cells T cells • After being notified by the macrophage that an intruder is present, T-cells send out a chemical messages to other immune cells. • Two types of T cells: Helper T and Killer T.

  17. Helper-T cells are also called TH, T4, or CD4 cells (they contain CD4 proteins) Helper T cells are the “general” of the immune system military. They send chemical messages that direct the war against infection. HELPER-T cells

  18. Two types of B-cells: 1) Plasma B-cells: produce antibodies specific to a particular invader 2) Memory B cell: “remembers” pathogens so that immune response is sped up when exposed to pathogens more than once. Plasma B cells B-memory cells B cells

  19. Produced by Plasma B cells. Antibodies are specific to only one type of invader Able to recognize and bind to antigen surface markers (“nametags”) on the invading pathogens. A coat of antibodies can disable, destroy or bring attention to the intruder as foreign objects in the body. antibodies Antibodies

  20. What happens when you are sick?

  21. Skin Mucous Membranes Enzymes & acids Inflammatory response If the pathogen is successful at doing this, then that means it is killing cells! Pathogen evades the 1ST & 2ND defense barriers

  22. Macrophages find the pathogens and immediately begin destroying them. Antigens from the destroyed invader are displayed on the macrophage surface. Macrophages are alerted

  23. The Helper-T cell with the correct receptors binds to the antigen markers displayed on the macrophage surface. As the cells bind, the macrophage activates the Helper-T cell. Macrophages signal other immune cells

  24. Helper T signals B cells • Helper T cells release chemicals that signal the killer T cells and B cells.

  25. Antibodies attach to the receptor sites on the pathogen and neutralize it. Antibodies “tag” pathogens for future reference. Plasma B cells produce unique antibodies for the specific invader. Some B cells make antibodies

  26. The killer T cells hunt for disabled pathogens and destroy the intruder. They also scan for cells invaded by pathogens and destroy the cell along with the pathogen inside. Killer T gets to work!

  27. Some B cells are memory cells • Other B cells are responsible for “remembering” the pathogen • The next time it comes into the body, the cells remember it and the immune response can take place much more quickly.

  28. antigen antibody macrophage Helper T cell Killer T cell Plasma B cell Memory B cell Suppressor T cell 2. Antigen Virus 1. 3. 7 Suppressor T cell 6 Memory B cell once virus eliminated, shut down immune response retains chemical memory of viral antigen; faster secondary response 5. 6. 3 Helper T cell 7. acts as general; regulates immune response 4 Killer T cell 5 Plasma B cell 4. 1 Macrophage scans & kills cells infected with virus produce antibodies to counteract antigen scouts for pathogens; looks for “self” marker Immune Response 2 macrophage engulfs virus; displays antigens on cell surface

  29. Primary Response first encounter to a pathogen, response through production of antibodies Secondary Response response next time the pathogen is encountered, memory cells already know how to fight it, fast response, immune to disease 350 300 250 B cells/mL of blood 200 150 100 50 0 B cells-no exposure 1 2 3 4 5 6 7 8 Time, in Hours B cells-after 1st exposure B cells-after 2nd exposure Immune Response after exposure to a pathogen

  30. How to you become immune to a disease? Natural Immunity - actually had the disease and got well Artificial Immunity - injection of vaccine (weakened/mild form of pathogen) to force your body to develop immunity IMMUNITY

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