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Disease:

Disease:. Bacteria and Viruses. Disease. Contagious diseases are caused by pathogens: Pathogen- any disease-causing agent, especially bacteria and viruses. Immune Response. 3 lines of defense against pathogens: Skin - acts as barrier

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Disease:

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  1. Disease: Bacteria and Viruses

  2. Disease • Contagious diseases are caused by pathogens: • Pathogen- any disease-causing agent, especially bacteria and viruses

  3. Immune Response • 3 lines of defense against pathogens: • Skin- acts as barrier • Injured cells send chemical signal- increases blood flow to injured area • T Cells/B Cells- weapon that destroys a specific pathogen

  4. Human Immune System

  5. T Cells • A type of lymphocyte (or WBC) • Main source of immunity • 2 types: “helper” and “killer” • Helper T Cell- recognizes virus infected cell, sends signal • Killer T Cell- binds to infected cell and destroys it

  6. B Cells • Another type of lymphocyte • Makes antibodies against pathogens • Antibody-recognize antigens on surface of cell, bind to it, and destroy it

  7. Antibodies recognize antigens • Antigen-foreign substance on surface of cell that triggers an immune response (attack it!) • When you fight off a disease, you develop antibodies against it to prevent getting disease again • Also get antibodies from mother’s milk

  8. Different types of Immunity • Active Immunity- immune response triggered by your own body from actively having disease (usually life-long immunity) • Passive Immunity- antibodies passed from mother’s milk to child’s body (usually not permanent but protects child for some time)

  9. What is a bacteria? • Bacteria- • prokaryotic cell (no organelles) • Unicellular • Spherical, spiral, or rod shaped • Reproduces asexually (fission)-identical copy

  10. Common Diseases • Caused by Bacteria: • Streptococcus (Strep Throat) • Conjunctivitis (Pink Eye) • Lyme Disease (from infected Tick bites) • Anthrax

  11. What is a Virus? • Virus- strand of DNA enclosed in a protein capsule that causes disease • Non-living! • Can only replicate in body of its host • Has ability to mutate into different strains (Iike influenza and different flu shots)

  12. Virus Structure • DNA enclosed in capsid (protein coat)

  13. Common Diseases • Caused by virus: • HIV (virus that causes AIDS) • Influenza (the common flu) • Smallpox (pretty much eradicated now)

  14. Vaccinations • Vaccines- injection of weakened or dead virus that triggers production of antibodies • Increases immunity to a viral disease

  15. Antibiotics • Antibiotic- substance or compound that kills, or inhibits the growth of bacteria Ex. Penicillin Question: Should your doctor prescribe you an antibiotic for the common flu?

  16. Protect Yourself!!! Protect Yourself! (List of ways to avoid common pathogens)

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