Ch 5 Requirements for Infection

  1. What is a portal of entry?
    Any point at which organisms can enter the body
  2. What are 2 protection mechanisms against pathogens for the stomach?
    Stomach acid and bile; they produce hostile enviro that limit the survival of pahtogens
  3. Fimbriae
    Short hair like appendage found exterior to the cell wall. It is used as a mechanism for staying in the host during infections.
  4. Capsules
    A protective structure found around the outside of a bacterial cell. It can be made up of polysaccharides, polypeptides, or a combo of both.
  5. Adhesion
    A protein or glycoprotein found on attachment pili or in capsules that helps microorganisms attach to host cells
  6. Mycolic Acid
    A waxy substance found in the cell wall of certain bacteria, such as the genus Mycobacterium.
  7. What do fimbriae, capsules, adhesions, and mycolic acids do for bacteria?
    They give the bacteria the advantage of proctecting itself against the defense mechanisms of the host cell
  8. ID 50
    Infectious dose 50%. The number of organisms required for 50% of the host population to show signs of infection.
  9. LD 50
    Lethal Dose 50%. The number of organisms required to kill 50% of the host population.
  10. How is virulence related to LD50 and ID 50?
    • High virulence: LD50 &ID50 is low.
    • Low virulence: LD50 &ID50 is high.
  11. Leukocidins
    An exotoxin produced by many bacteria that kills white blood cells, including phagocytic cells.
  12. Hemolysin
    An enzyme that destroys red blood cells
  13. Coagulase
    A pathogen-produced enzyme that causes fibrin clots to form in the blood of a host. Can be used by both host and pathogen during an infection.
  14. Kinase
    Enzymes that break down fibrin and dissolve clots. Can be used by a pathogen to overcome attempts by the host to wall of the infection, thereby ensuring spread.
  15. Hyaluronidase and Collagenase
    Enzymes that break down connective tissue and collagen in a hsot, thereby allowing infections to spread. Ex: gas gangrene involves the destruction of connection tissue.
  16. What are the three types of exotoxins?
    • Cytotoxins
    • Neurotoxins
    • Enterotoxins
  17. Cytotoxins
    Kills cells with which they come in contact
  18. Neurotoxins
    Interfere with neurological signal transmission
  19. Enterotoxins
    Affect lining of digestive system
  20. What are symptoms of endotoxin poisening?
    Chills, fever, muscle ache & weakness
Card Set
Ch 5 Requirements for Infection