Eli5 How does food and liquids remain inside the stomach and not “leak out of your mouth” whilst being in space?

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Eli5 How does food and liquids remain inside the stomach and not “leak out of your mouth” whilst being in space?

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11 Answers

Anonymous 0 Comments

Your esophagus is a muscle and can restrict itself, effectively closing your mouth off from your stomach. Same reason nothing will come out if you were to be held upside down.

Anonymous 0 Comments

Short answer? Sphincters.

Anonymous 0 Comments

There is a muscle at the top of your stomach. It is a ring that holds closed unless you are swallowing or puking. This is why you can be upside down and won’t have what’s in your stomach pour out. Same thing as why you don’t pee yourself each time you stand as there is one right at the exit of your bladder. These types of muscles are all through the body and control the flow of liquids.

Anonymous 0 Comments

Your stomach has muscles around the opening to keep food inside. Thus why you aren’t vomiting stomach acid when performing a hand stand or otherwise upside-down. Furthermore, muscles around your esophagus will actively push food down towards the stomach in a process called peristalsis, allowing you to properly swallow and eat regardless of orientation or if floating around in space.

Anonymous 0 Comments

All good answers and just reaffirming this is not a dumb question, humans and other mammals have a series of “valves” and muscles that keep pushing the food actively from the mouth to the butt.

Birds, for example, don’t. They need gravity to swallow and do the work. Hence why we sent monkeys, apes, and dogs into space to test early space ships and not smaller, easier, or cheaper animals.

Anonymous 0 Comments

The same way they don’t leak out of your mouth when you do a handstand, or lay on your stomach. You have muscles that keep things in place.

Anonymous 0 Comments

If you really want to blow OP’s mind, tell him about [peeing upside down](https://www.reddit.com/r/NoStupidQuestions/comments/c21h5j/can_you_pee_upside_down/erh0hg3/).

Anonymous 0 Comments

A lot of answers here but none of them admit, yes, sometimes it does leak out in space. We have natural rings of muscle that close things off, that’s why you don’t just vomit if you bend over at the waist on earth.

However..food and liquids don’t really remain in the stomach in space. If you burp in space, you will likely also push out stuff in your stomach. (There is no gravity ensuring the lighter, burped gases are the only thing at the top of your stomach.)

Anonymous 0 Comments

Literally, the same reason why you don’t shit yourself.

See the anus is a ring muscle, called sphincter, you have one of those at the entrance and exit of your stomach, and anotherone that separates the small and large intestines.

Anonymous 0 Comments

There is a sphincter valve at the top of your stomach where it connects to the esophagus. Normally unless swallowing (or in case of dysfunction , which can cause acid reflux for example) it is closed and prevents food from emerging even when hanging upside down, for example.