Human defence system

• what does the non-specific defence system work to do

  prevent pathogens from entering the body
• skin

  • acts as a physical barrier
  • produces antimicrobial secretions to kill pathogens
  • skin flora compete with bad microorganisms for space and nutrients
• nose

  • has hairs and mucus wich prevent particles from entering your lungs
• trachea and bronchi

  • secrete mucus in order to trap pathogens
  • cilia (hair-like structures on cells)beat to waft mucus upward so it can be swallowed
• stomach

  • produces hydrochloric acid that kills pathogens in mucus or food and drink
• what are the 3 functions of white blood cells

  1. phagocytosis

  • engulfing and consuming pathogens
  • destroys pathogens meaning they can no longer make you ill

  1. producing antibodies

  • produces a complementary antibody that binds to the antigen
  • if pathogen is detected again, the antibody can be produced faster and the host will not feel the illness

  1. producing antitoxins

  • neutralise toxins released by the pathogen by binding to them