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Non-specific defences
1. Barriers
  1. First line of defence
  2. Skin destroys some pathogens; saliva in mouth kills most pathogens, hydrochloric acid in stomach kills others; salty tears kill most entering your eyes; mucus membrane to trap and destroy pathogens.
  3. The enzyme LYSOZYME plays an important role b/c it destroys the cell walls of bacteria.
2. Inflammation
  1. Second line of defence
  2. Prevents pathogens from spreading to nearby tissues
  3. Destroys and removes pathogens and damaged cells.
  4. Prepares your body for healing
  5. White blood cells involved - macrophages (enlarged monocytes) and neutrophils
    1. Phagocytosis occurs
      Annotations:
      - Phagocytosis is when the macrophages attached themselves to the pathogen, surround it, and then chemically destroy it using enzymes.
  6. Fever occurs if whole body approach is needed.
Specific defence
1. Immune Response - Third line of defence
  1. 1. Identify & activate response
    1. B cells respond to antigens by designing and making antibodies.
    2. Helper T cells (T cells) coordinate the immune response; activate B cell to produces antigens and then activate the killer T cells.
  2. 2. Kill pathogen
    1. Killer T cells (K cells) destroy any disabled pathogens.
  3. 3. Remember pathogen
    1. Memory B cells (M cells) retain information about foreign antigens and the antibodies that fought them.
      1. Memory B cells immediately recognise if the same pathogen enters the bdy and very rapidly produce the antibodies to destroy them.

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Our three defences to fight diseases

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	Created by Shirley Barker over 10 years ago