How does the stomach work in space? Do astronauts feel constant need to throw up since the contents are bouncing around inside?

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How does the stomach work in space? Do astronauts feel constant need to throw up since the contents are bouncing around inside?

In: Biology

13 Answers

Anonymous 0 Comments

Óir bodies are very good at keeping everything compact. While aided by gravity, one can digest anything in 0-G, and even upside down, since the entire process is muscularly controlled.

But no – astronauts get extensive training to *not* throw up. Most are/were former fighter pilots and have really good control.

Anonymous 0 Comments

Our intestines are actually kept together by a membrane called peritoneum, so even on Earth they’re not moving around that freely. In space, due to the absence of gravity, organs do tend to go slightly upward.. however nausea isn’t caused by the “organs moving around”, but by the brain that has to adapt to the no-gravity condition and causes us to have balance and coordination problems. And honestly the major problem for astronauts is that if they don’t do workouts while in space, they’d weaken their bones and muscles.

Edit: I realized that my answer was not pertinent, hope this answers your question.
When we ingest food, the muscle force that on Earth pushes food down to our stomach is strong enough to do it when we’re upside-down or even in space. After that, food reaches the stomach: processes that transform food into a sort of fluid (while breaking up fats and proteins in their simple forms) actually works the same even without gravity and the food they eat is full of nutrients but is pretty light, to prevent nausea…

English is not my first language, I apologize in advance for any mistakes…

Anonymous 0 Comments

Most people can hang upside-down without puking. The human digestive tract is lined with muscles that keep everything in place and moving in the right direction. If you can physically keep from puking at -1G (by your frame of reference) then you can certainly keep your lunch down in 0G.

Going beyond your question though, space sickness happens because the bones and fluid in your inner ear that determine your orientation float around. You can have the ceiling as your frame of reference as “up” and then a small shift causes your inner ear to register it as down, left up, behind. You get nauseated from that and you puke.

Anonymous 0 Comments

Space sickness is a common side effect of micro-gravity. Vomiting is controlled more by the ear than the stomach. It is when what the eyes see doesn’t match what the ears are experiencing. Space sickness is similar to all motion sickness. Your eyes see that you are moving while your ear registers you are standing still. Most astronauts experience this for the first few days up to week in space. The space program usually selects people less prone to this for space flight.

I know you didn’t ask, but I find this stuff fascinating. The real bodily function problem of micro-gravity is defecating. Gravity is the main force to separate stool from the anus. Early astronauts had to use their hands and a bag to separate stool. Now most spaceships have a vacuum.

Edit: Reversed eyes/ears.

>Space sickness is a kind of motion sickness that can occur when one’s surroundings visually appear to be in motion, but without a corresponding sense of bodily motion.

https://en.wikipedia.org/wiki/Space_adaptation_syndrome

Anonymous 0 Comments

A stomach is also more a wet bag than a box or bottle. There’s no big open space to fill. The contents can slosh around when you fill it up.

You have a sphincter (round muscle like your butthole) that holds things in at each end. There’s a lower esophagal sphincter at the top of the stomach that keeps the digesting food down, and a pyloric sphincter at the bottom that lets it into the intestines when it’s digested enough to move on.

When that esophagal sphincter gets weak, the result is reflux. It would be very unpleasant to be in space and have that aggravated.

Anonymous 0 Comments

Do we throw up every time someone does a cartwheel? Your stomach is capable of withstanding being upside down, on your side. It’s contained

Anonymous 0 Comments

Think of the stomach like a muscular water balloon with two ends being held shut. The ends are held shut with muscles like your butt hole called sphincters. When it’s empty, it’s “deflated,” and when you fill it, it expands to hold the solids or liquids you put in it. If you were to hang upside down on earth, the upper sphincter keeps the stuff in. Just like in space, the sphincters hold it all in. During digestion, the stomach muscles expand and contract to squish and mix the stuff inside. When it’s broken down the foods enough, the lower sphincter opens and the stomach muscles squeeze the stuff out to move it along to the next stage of digestion, like letting go of the end of a water ballon, it will squeeze it all out. Think of squishing and shaking a water balloon. There’s not much open space in your stomach, unless you ingest a lot of gas, for stuff to “bounce around,” and your stomach contents are always being squished and mixed. Though gravity can help, digestion doesn’t rely on it to work. The muscular action the body uses to move liquids and solids through it is called peristalsis and is why we can eat,l and drink while upside down or laying down.

If you did feel like vomiting in space, it would likely be an issue called space sickness, which is a form of motion sickness where your visual system and your vestibular system tell your brain two different things about your motion. But that’s another ELI5

Anonymous 0 Comments

And what about farts!? This has plagued me for a long time. How does the gut release gas in 0G? Full disclosure, I don’t really understand how it does it down here. Life is full of mysteries

Anonymous 0 Comments

So does having a hiatal hernia mean I cannot be an astronaut!?

Anonymous 0 Comments

Do you start vomiting when lying in your bed? Gravity is no longer pulling your ingested food down, is it?

Only if you have problems with the muscles on top of your stomach, which is called acid reflux. The contents of the stomach are held down by muscles, not by gravity.