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Chapter 3

Chapter 3. The Immune System. 3.1 The Immune System . Pathogen = disease causing invaders! •Reducing transmission of infectious diseases by washing hands and sterilizing equipment. Four Ways to Transmit I nfectious D isease. 1 .Direct contact – shaking hands, sharing bodily fluids

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Chapter 3

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  1. Chapter 3 The Immune System

  2. 3.1 The Immune System • Pathogen = disease causing invaders! •Reducing transmission of infectious diseases by washing hands and sterilizing equipment

  3. Four Ways to Transmit Infectious Disease 1.Direct contact– shaking hands, sharing bodily fluids with an infected person 2. Indirect contact – being near an infected person 3. Water and food – eating or drinking infected food or water 4. Animal bites – being bitten by an animal that is infected

  4. First Line of Defence • Skin and the linings of the internal body systems (physical barrier) • Sweat and oil on the skin (acidic) • Gastric juices • Mucus and cilia lining the nose

  5. Second Line of Defence • When a pathogen passes the first line of defence… Innate immune response •Quick and non-specific – response is the same for anything the body recognizes •Usually against viruses and bacteria (colds and flus) •Flow of fluid, cells, and dissolved substances from the blood to site of infection •Causes a fever, swelling, and redness of the area = inflammation •Increase in white blood cells (phagocytes) – swallow invader cells

  6. Continued • Acquired Immune Response • Highly specific attack on a particular pathogen = antigen • Antigen – a substance the body does not recognize • Pathogen - disease causing antigen • Antigen – non-living particle or substance • Involves two types of white blood cells (B cells and T cells)

  7. “B Cells” • B Cells recognize antigens present in the body • They produce antibodies to fight them • Antibodies attach and destroy both antigens and pathogens

  8. “B Cells Continued • B Cell recognizes and produces antibodies that will cover the antigen • These antibodies allow the WBC to recognize and destroy it or prevent them from entering body cells • Body then produces large numbers of these particular B Cells to keep fighting the antigen

  9. “T Cells” • This occurs when an antigen actually enters the body cells • WBC signal the production of helper T Cells • Helper T Cells recognizes the antigen and signals for more B Cells • Once the attack is over some of these antibodies remain in the body for future attacks

  10. “T Cells” continued • Killer T Cells directly kill antigens • Activity immunity – means your body remembers which antibodies should be used to attack a pathogen that has infected before • These are now called memory B Cells and can be reactivated if a pathogen reappears later on

  11. Textbook Questions Page 109 #1, 2, 5-13 &17

  12. 3.2 Factors Effecting the immune system • Vaccines are weakened versions of a disease pathogen that are given to protect them from getting later • Weakened form of the of the disease • Given by needle or liquid form • Some need to have a booster shot – updates the antibodies

  13. Allergies • High sensitivity to some substance • Immune system kicks in • Allergen – substance that causes an allergic reaction • Allergens could be a number of things – pollen, dust, foods, etc. • Symptoms of an allergy – runny nose, watery eyes • Result of histamine release in the body • Antihistamines – reverse the effects of the body’s regular response • Severe reaction = anaphylactic shock – swelling, breathing problems and even death if not reversed • To reverse this you would have to give a shot of adrenaline – EPI PEN

  14. Aids • Infection of the immune system – leading to health complications • 11 million people have died of AIDS • Caused by HIV virus • Transmitted by blood and semen • No known cure

  15. Ways to keep your immune system healthy • Eat a well balanced diet • Keep up your hygiene • Keep your home clean • Avoid smoking and drugs • Get rest and exercise • Vaccinations up to date • Don’t share bodily fluids with others

  16. Homework Textbook Questions Page 117 # 2, 3, 7-11, 16&17

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