Eli5 How does food and liquids remain inside the stomach and not “leak out of your mouth” whilst being in space?
In: 82
Most of us have a vision of the stomach that was shown to us in TV and cartoons – a big cavernous space with a big hole in the top and a pool of acid in the bottom, where everything we eat comes flying out of the hole and crashes into the acid pool with a big splash.
In reality, our body doesn’t really have any big empty spaces, but everything squished up together. So rather than the big cavern, our stomach is more like a water balloon full of acid with a knot holding it shut. When we eat something, it is pushed down your throat by the muscles that make up your esophagus (for a good example, see if you can find a video of a snake eating something really big and watch it get pushed along its body).
At the top of the stomach there is a muscle that holds it shut like the knot of the balloon – it opens up just enough to let the food be pushed inside, then closes up again before anything can escape.
Inside it is completely full of stomach acid and whatever you have eaten, with no air – sometimes gas will be produced (like when you consume a fuzzy drink), which the muscle at the top quickly and carefully let’s out in the form of a burp.
At the opposite end, there is another muscle controlling what is let through into your intestines in the same way.
So to answer the original question, when laying down, upside down or in zero gravity, the muscle between the esophagus and stomach acts like a door, only opening to let food through when it wants to, otherwise closing up to stop food flowing back up your throat as you dangle upside down.
And because everything is squished in together and solid without big air pockets, it doesn’t really slosh around quite like you would expect, but just stays in place
Latest Answers