Cards (15)

  • Lymphocyte = white blood cells involved in the immune response
  • Self antigen = molecule on the cell surface membrane of your own body cells
  • Immunity = means by which the body protects itself from infection
  • Non-self antigen = antigen that is not part of the body's own tissue
  • Pathogen = a microorganism that causes disease in a host organism.
  • The two types of defence mechanisms are specific and non-specific
  • Non specific responses are immediate and are not specific to a particular pathogen.
  • Specific responses are slower and specific to each pathogen
  • Examples of non specific defenses are physical/chemical barriers and phagocytosis
  • Examples of specific responses are B and T lymphocytes
  • Examples of barriers are skin, cilia, stomach acid and tears
  • Skin
    • outer layer consists of flat, dead cells that consist mainly of the protein keratin
    • forms a tough barrier
  • Cilia
    • Tiny hair-like structures lining the nose and gas exchange system
    • Bathed in mucus which is wafted to the back of the throat where it can be swallowed
  • Stomach acid
    • low pH kills pathogens
  • Tears
    • contain lysozymes which digest the cell walls of bacteria