[ELI5] If our mouth is full of bacteria, how do mouth injuries heal and not be considered lethal?
In: Biology
The bacteria in your mouth are usually expected to be there. The body is able to keep them in check. When you have an injury, like a cut inside your cheek, some of that bacteria can get into the skin and grow out of control.
In some cases, it can lead to major infections and death.
You can limit the amount of harmful bacteria by brushing your teeth and rinsing with an antiseptic. And if you have an abscess, you can drain it and kill bacteria with salt solutions and antibiotics.
But for normal, every day cuts, like you bit your lip too hard? Your body can handle a bit of it.
It’s precisely because our mouths are full of bacteria that we’ve evolved some pretty great mechanisms to keep wounds in our mouths from becoming infected.
First, many of the bacterial species that live in our mouths don’t make us sick, and in fact, it’s beneficial for us to have those types of bacteria there, because they use up all the resources and thereby prevent disease-causing bacteria from growing in large numbers.
Second, our saliva contains a number of proteins and enzymes that help prevent infections. Some of these proteins and enzymes directly kill bacteria or prevent them from replicating, and others prevent the bacteria from sticking to the cells in your mouth, so they become trapped in your saliva when you swallow it, and your stomach acid kills them.
Third, our mouths have a lot of blood vessels and they’re very close to the surface. This means that if you get a wound, bacteria-killing white blood cells can reach the wound fast and in large numbers to prevent an infection from setting in.
Fourth, the cells in our mouths replace themselves much faster than cells elsewhere. This means that open wounds close up faster, so any opening for bacteria to enter doesn’t last very long, which reduces the chances of an infection setting in.
There are probably some other factors that I’m not remembering, but the general gist is that our mouths have a number of special defenses to bacterial infections.
Aren’t are entire bodies covered with and filled with bacteria? Not all bacteria is bad. Gut health is all about encouraging good bacteria.
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