Human Defence Systems

• The non-specific defence systems of the human body against pathogens include the:

  • Skin
  • Nose
  • Trachea and Bronchi
  • Stomach
• The skin defends against pathogens through the skin barrier, which is a physical barrier that prevents pathogens from entering the body.
• The nose contains hair and mucus to trap pathogens before entering the breathing system.
• The trachea and bronchi are covered with tiny hairs called cilia which are covered in mucus which can trap pathogens, which then waft the mucus upwards towards the throat where it is swallowed into the stomach.
• The stomach protects against pathogens through the usage of hydrochloric acid, killing pathogens.
• White blood cells help to defend pathogens by:

  • Phagocytosis
  • Antibody Production
  • Antitoxin Production
• Phagocytosis is the engulfing of pathogens by a white blood cell, which then are destroyed by enzymes.
• Antibodies are protein molecules produced by white blood cells. They stick to pathogens and destroy them. They are very specific and need to be developed against specific pathogens.
• Antitoxins are chemicals that stick to toxin molecules and prevent them from damaging cells.