THE INNATE IMMUNE SYSTEM - MECHANICAL BARRIERS
As well as a physical and chemical barriers to infection, our bodies also have mechanical barriers to prevent infection and damage.
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We have already mentioned tears in relation to chemical barriers, but they also have a mechanical action that helps to prevent infections. |
The very act of crying allows the tears to wash away any micro-organisms or dirt on the very delicate eye - so another reason to cry!
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If you get an upset stomach due to infecting pathogenic micro-organisms, then you may well vomit, and this mechanical action of vomiting as well as getting rid of the infected foodstuffs inside your stomach will also get rid of a lot of the pathogenic micro-organisms that caused the problem. |
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We can also look at the mechanical movement of cilia in the bronchial tubes and nasal passages. |
These tiny hairs are continually moving, and what they do is trap infectious micro-organisms and dirt in mucus and then slowly push it to the exterior of the body in a 'wafting' movement.
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Finally, in this very brief look at the mechanical barriers to infection, we need to consider the acts of coughing and sneezing. |
When you cough or sneeze, you expel millions of viruses (and possibly bacteria if you have a bacterial infection) out of your body and into the surrounding environment.
This is beneficial to you because if these micro-organisms are outside of the body, then they cannot be causing problems to you.
Unfortunately, these mechanical actions of yours (coughing and sneezing) are of no benefit to the poor person sitting next to you on the bus or train, who is likely to receive a megadose of your micro-organisms, and so may become infected themselves.