everything you need to know about pathogens!!!

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  • Created by: Jess
  • Created on: 21-02-10 18:26

pathogen- what is disease?

  • A 'micro-organism' is a single-celled organism that is too small to be seen without a microscope.
  • micro-organisms include: bacteria and viruses.

what is meant by disease?

  • disease suggests a malfunction of body or mind which has an adverse effect on good health.

For a micro-organism to be considered a pathogen it MUST:

  • gain entry to the host,
  • colonise the tissues of the host,
  • resist the defences of the host
  • cause damage to the hosts tissues

pathogens include: bacteria, fungi and viruses.

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pathogens entering the body.

  • If a pathogens enters the host and colonises its tissues then an infection results.
  • Disease occurs when an infection leads to recognisable syptoms.
  • When a pathogen is passed from one individual to another it is known as transmission.

How do micro-organisms enter the body?

micro-organisms enter the body through interfaces. (an interface is a surface or boundary linking to systems). Two types of interface are:

  • the gas-exchange system. some pathogens that enter this way are: influenza, tuberculosis and bronchitis.
  • the digestive system. Some pathogens that enter this way are: cholera and typhoid.
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how does the body prevent pathogens from entering?

The body has a number of natural defences that prevent pathogens from entering these include:

  • a mucous layer that covers exchange surfaces and forms a thick sticky barrier that is difficult to penetrate.
  • the production of enzymes that break down pathogens.
  • the production of stomach acid, which kills micro-organisms.

How do pathogens cause disease?

pathogens affect the body in two main ways:

  • by damaging the host tissues.
  • by producing toxins.
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