Immunity

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Microbes are the name given to bacteria, fungi and viruses that try to eneter the body. Many of them are harmelss but some, callled pathogens can cause disease and in extreme cases death. 

Micorbes took a long time to be discovered as they were so small that a powerful enough microscope needed to be invented in order to see them.

One of the first people to relise they exist was Semmelweis. He was a Hungarian doctor who worked in the labour department of a hospital. In the department there were 2 wars, one was used to teach doctors on and the other was run by nurses. Neither of the two wards were cleaned often however the ward in which doctors were tuaght had a much higher death rate than the one run by nurses. 

As an experiment to reduce the number of deaths Semmelweis made all of the docots was their hands in chlorine water, the result was that there were much fewer deaths. This was on of the first ways that infection was controlled in hospitals. 

Natural Barriers our our bodies defence to different micro-organisms that will try and enter our bodies through the many different openings we have. We have many different deffence mechanisms to stop infections getting into us causing damage (natural barriers) these include: 

  • The skin - a physical barrier to many micro-organisms
  • The stomach - contains hyrdrochloric acid to kill of microbes
  • The eyes - contain tear ducts to wash out any infections
  • The nose and airways - contain mucus to trap microbes
  • The ears - contain sticky wax to trap microbes
  • Pores in our skin which contain sweat - this washes microbes out 
  • Penis/Vagina/Anus - contain fluids to wash microorgansims out
  • Cuts - bleed out to wash out any microorganisms that are trying to get in

However despite all our bodies natural barriers micro-organisms still do get in, if they happen to find there way into our bodies they now have a warm and comfortable enviorment ideal for them to reproduce which is how we can become ill. In such a case where microbes do enter our body we have more defence mechanisms in place to deal with them. 

Our White Blood Cells play a big role in keeping our bodies healthy. There are several different types. Some move around the body in the blood destryoing infections as they get in and some that are specilaist white blood cells which destroy specific micro-organisms. 

Phagocytes - this is the general type of white blood cell which moves around your body in your blood and engluf's and digets bacteria. Most of the time phagocytes can engulf and digest all of the microbes which enter our bodies (this is why we are healthy for the majority of the time) however occasionally new microbes enter our bodies that our phagocytes cannot detect thust they can not be destroyed. 

Lympocyte - This is a specialist type of white blood cell. They are surrounded by antibodies and have a way…

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