system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do you pee yourself when you're nervous/scared?

Is it some survival mechanism or is it just to make you feel embarrassed in public? Just wondering. Thanks!
gpt
This happens because the Limbic system which controls our "flight or Fight" response takes over the body when we are scared. 

In a normal state our bladder is set up to want to void its contents when pressure reaches a certain level. Our prefrontal cortexs prevents this from happening at random, and give us a level of control over the process. 

When we are overwhelmed by fear the limbic system takes over. The limbic system doesn't care about our bladder, and pushes all energy and focus on the muscles that will either help us fight or escape. That means that if the badder was at a point where the pressure is high enough that it wants to empty...well, the brain is no longer preventing it from happening. 

Bombs away.