Defence Against Diseases

Defence Against Diseases

1. Natural Immunity

   • White Blood Cells
     • For more about white blood cells:http://science.howstuffworks.com/life/human-biology/blood2.htm NOTE: This is very detailed and advanced. U do not need to know everything that it says on this site.
     • White blood cells can:
       • Ingest pathogens and destroy them
       • Produce antibodies to destroy pathogens
       • Produce antitoxins that neutralise the toxins released by pathogens
     • They are part of the immune system
     • They fight infections
     • In a normal adult body there are 4,000 to 10,000 (average 7,000) WBCs per microlitre of blood.
       • A microlitre is a millionth of a litre
     • They circulate in the blood so that they can be transported to an area where an infection has developed.
   • Once a particular antibody is made in your body it stays there
     • This means that whenever the harmful micro-organism comes into your body again the antibodies are much quicker at destroying it.
       • You are now immune
   • Making antibodies takes time
     • This is why people fill ill before they get better

2. Artificial Immunity

   • Vaccinations
     • Vaccination