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first line of defenceThe body’s first line of defence is its natural barriers which include:
- chemicals in tears
- chemicals in sweat
- stomach acid
second line of defenceNon-specific response inside the body to pathogens which have made it past the first line of defence.
- increased blood flow to the affected area
- white blood cells engulfing and digesting the pathogens
- formation of scabs to close the wound.
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)