Human defence systems

• The human defence systems are:

  • Skin
  • Hair and mucus
  • Trachea and bronchi
  • Stomach
• Skin:

  • Barrier to pathogens
  • Secretes antimicrobial substances which kill pathogens
• Hair and mucus:

  • Trap particles that could contain pathogens
• Trachea and bronchi:

  • Secrete mucus to trap pathogens
  • Lined with cilia - send mucus to back of throat to be swallowed
• Stomach:

  • Produces hydrochloric acid - kills pathogens
• • The immune system destroys pathogens that have entered the body
• White blood cells help defend through:

  1. Phagocytosis - engulf foreign cells
  2. Antibody production - rapidly producing specific antibodies to lock onto antigens of invading cells to be killed, carried around body, infection of ssme pathogen will cause antibodies to be rapidly produced - natural immunity
  3. Antitoxin production - counteract toxins produced by invading bacteria