Fighting Disease

• The skin acts as A barrier to pathegons
• The skin also secretes anti-microbial substances (sebum) which kill pathogens
• hairs and mucus in your nose trap particles that could contain pathogens
• trachea and bronchi secrete mucus to trap pathogens and are lined with cilia which waft mucus up the throat to be swallowed
• the stomach contains hydrochloric acid
• the immune system attacks pathegons
• 1. white blood cells engulf foreign cells and digest them. this is called phagocytosis
  2. every pathogen has unique molecules on its surface called antigens
  3. when a WBC detects a foreign molecule they produce antibodies to lock onto invading cells so they can be found and destroyed.
  4. antibodies reproduce rapidly and find other foreign cells
  5. the WBC then recognise the pathogen if it was invade again an destroy them so the person wont get ill
• antitoxins are produced to counteract toxins produced by invading bacteria
• vaccinations inject small amounts of dead or inactive pathogens . these have antigens that your body will attack by producing antibodies.
• PROS:

  vaccines control communicable diseases spreading and epidemics
• CONS:

  • Vaccines don't always work
  • you can get bad reactions to vaccines