#TodayILearned that the human body has a reflex called RAIR (Rectoanal Inhibitory Reflex) with which the top parts of your anal canal *involuntarily* allows its content to lower just a bit, so that it touches the lower third, wherein cells then SAMPLE the content to tell your brain whether you have poop or fart in there. Once the sampling is done, the content is then raised again. And that’s how you know if it’s safe to relax your sphincter to release a fart, or if you’re going to poop if you do that. This sampling happens a few times an hour.
The only problem is that your cells sometimes cannot tell the difference between liquid and gas, and that’s where sharts come from.
~~The more you know~~