Fighting diseases

• Human body's features for fighting disease

  • Sophisticated defence system
  • Skin acts as barrier to pathogens
  • Nose and mucus trap particles
  • Trachea and bronchi secrete mucus
  • Trachea and bronchi lined with cilia
  • Stomach produces hydrochloric acid
• Immune system's attack on pathogens

  1. Consuming pathogens

  2. Producing antibodies

  3. Producing antitoxins
• White blood cells


  Most important part of immune system, patrol for microbes
• Antibodies


  Specific to the antigen (pathogen molecule), produced rapidly and carried around body
• Person infected with pathogen again


  White blood cells will rapidly produce antibodies to kill the pathogen
• If you have a low level of white blood cells, you'll be more susceptible to infections
• HIV weakens the immune system, making it easier for other pathogens to invade
• Skin, nose, trachea and bronchi are adapted to defend against the entry of pathogens
• Deciding whether to have a vaccine depends on weighing the pros and cons