Preventing pathogens entering

Our natural defenses to stop pathogens from entering.

This tutorial is aimed for Key stage 3/GCSE and A level.

A pathogen is a disease causing microorganism. We have many natural defences to stop pathogens from entering the body.

Our skin is our biggest natural protector. It stops pathogens from entering. If the skin is cut then blood will for a clot to prevent pathogens from entering.


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Our eyes produce tears that contain antibacterial chemicals.  This stops pathogens entering through the eyes.

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When we breathe in dust and pathogens enter our airways. In out trachea or airways there are goblet cells which secrete mucus. The mucus is sticky and so it traps pathogens. The cilia then move the mucus and pathogens upwards to the top of the throat. Here, swallowing will occur where the mucus and pathogens will go down the oesophagus into the stomach. In the stomach there will be hydrochloric acid that will kill the bacteria.


Image supplied by Alila Medical Media. Click on the link to see other cell images.