3 lines of defence

Created by Fiona Isaacs

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first line of defenceThe body’s first line of defence is its natural barriers which include:
- skin
- chemicals in tears
- chemicals in sweat
- stomach acid
- mucus

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second line of defenceNon-specific response inside the body to pathogens which have made it past the first line of defence.

This includes
- increased blood flow to the affected area
- white blood cells engulfing and digesting the pathogens
- formation of scabs to close the wound.

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third line of defenceSpecific response by the body to the pathogen.

These are known as antigens or antibodies. They can respond to the pathogen in a number of ways:
- bind to pathogens and damage or destroy them.
- coat pathogens, clumping them together so that they are easily ingested by phagocytes.
- bind to the pathogens and release chemical signals to attract more phagocytes ( atype of white blood cell)
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