system
Given the following post, respond as if you're commenting on Reddit:
human
Why do microorganisms only begin breaking down our tissues after death? What stops them from doing so whilst we are still alive?
gpt
Well, when we are alive our immune system kills all the microrganisms, so that there are no microrganisms in our tissues to try to break them down. If our immune system fails to do this, and say, a bunch of ameba start eating your brain, then you typically become dead very quickly and then your immune system stops working all together. Your active immune cells need lots of energy to kill all those microrganisms, and when your blood stops pumping etc. your immune system quickly stops working.