Disease and Immunity: Disease

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  • Created by: Frankey
  • Created on: 01-01-11 20:00

Pathogens Cause Infectious Diseases

  • pathogen: any organism that causes disease
  • includes microorganisms and larger organisms e.g. tapeworms
  • includes bacteria, fungi and all viruses


Pathogens can Penetrate an Organism's Interface with the Environment

  • enter the body through the organism's surface of contact/interface with the environment
  • 3 main interfaces:
    • gas-exchange system
      • breathe in air containing pathogens
      • most trapped by mucus
      • cilia beat and move mucus to remove it
      • some reach alveoli, invade cells and cause damage
    • skin
      • damage to the skin can allow pathogens on the surface to enter the bloodstream
      • blood clots to prevent this
      • some may get in before the blood clots
    • digestive system
      • eat and drink food containing pathogens
      • most killed by acidic conditions in stomach
      • some may survive
      • invade the cells of the gut wall

Pathogens Cause Disease by Producing Toxins and Damaging Cells

  • despite protective mechanisms pathogens can successfully enter the body
  • they cause disease in two main ways:
    • production of toxins
      • many bacteria release toxins
        • e.g the bacterium that causes tetanus produces a…


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