Preventing and Fighting Disease

Preventing and Fighting Disease

1. Natural Defence System

   • Skin
     • Acts as barrier for pathogens and secretes antimicrobal substances
   • Hairs and mucus in the nose
     • Hair traps pathogen that have been breathed in, in mucus in the nostrils
   • Trachea and Bronchi
     • Secrete mucus to trap pathogens
     • Lined with cilia (hair like projections).
       • Waft mucus up to the back of the throat where it can be swallowed
   • Stomach
     • Produces hydrchloric acid which kills pathogens that make it far from the mouth

2. Preventing the Spread of Disease

   • Being hygeinic
     • E.g. washing hands before preparing food or after sneezing
   • Destroying vectors
     • Vectors that are insects can be killed using insecticides or by destroying their habitat so they can no longer breed.
   • Isolating Infected Individuals
   • Vaccination
     • People who have been vaccinated cannot develop the infection and then pass it on to someone else.

3. Immune System/White Blood Cells

   • Consuming/engulfing pathogens
     • Called PHAGOCYTOSIS
   • Producing Antibodies
     • Every pathogen has unique antigens on its surface.
       • White blood cells produce antibodies to lock onto this specific antigen.
         • Antibodies are then produced rapidly and carried around the body to find all similar bacteria or viruses.
           • If the same pathogen enters the body again, the white blood cells will rapidly produce the correct antibodies to kill it.
   • Producing antitoxins
     • Antitoxins counteract the toxins produced by invading the bacteria