For many, throwing up or vomiting is the most dreaded form of an illness. Some people even suffer from emetophobia — the fear of throwing up. As unpleasant as it is, your body is trying to do you a favor by making you throw up. It’s still a fairly horrible process but maybe understanding why and how it all happens will help just a little.
Why we throw up
The most common reason for throwing up is to get rid of something your body feels is harmful to you. This could be a nasty virus or a chemical that the body is worried about. Instead of allowing those items to pass through your entire body, your body works to remove them much quicker.
You can also throw up if you get very dizzy. Scientists are not quite sure why this happens but the leading theory is that your body systems become confused and just in case it is caused by something you ate, you throw up.
Not all animals throw up. Rodents lack the ability to throw up. Their brain lacks the throw up signaling process and their guts are not strong enough to send food back up. While this may seem like a great benefit, it is actually why rodent poisons work so well. The poisons that work so well on rodents would not work all that well on other animals as they would just be thrown up.
Some animals throw up in a much more dramatic way. When frogs eat something their body thinks is dangerous, they will throw up their entire stomach, which then turns inside out and hangs out of their mouth. The frog will clean the stomach before swallowing it again and moving on. Even more extreme, sea cucumbers will shoot out their entire digestive system when threatened in hopes to scare off predators. They are then able to grow another digestive system.
How we throw up
Your stomach is lined with special sensory cells that use a chemical called serotonin to communicate with the nervous system. When the stomach sensors detect something bad, they send a signal to the nervous system, which then sends a signal to your brain.
The command to throw up actually comes from your brain, not your stomach. When the brain receives enough signals, it will send a return signal to your stomach to start the process of vomiting.
After receiving the vomiting signal, your stomach muscles contract all at once, which squeezes everything while increasing the pressure. Then all at once the “cover” on your stomach relaxes and the contents of your stomach erupt out.
As horrible as it is, your body does help make things just a little better. First, most of the time your brain will give you that sick feeling to warn you that something is going to happen. Second, just before throwing up your body produces extra saliva, which helps protect your teeth from the strong acid. Third, the vomiting process releases chemicals in your body to make you feel better. So that “I feel better” feeling after throwing up is not just your imagination — it’s your biology working.
Contagious throw up?
Are you one of those people whoalmost throws up when somebody near you throws up? What’s the deal with that? Scientists believe it was evolution that produced that behavior in order to save you. Save you from what?
It is believed that the contagious throwing up developed in primates. Primates stayed in groups to forage for food. So, if one primate started throwing up, it might be helpful if that caused the others to throw up since they were likely eating the same food. That trait was passed down and down and still remains in some of us today. The trait is just sitting there waiting for somebody near you to throw up because just maybe you also ate the spoiled or poisoned food.
Mike Szydlowski is science coordinator for Columbia Public Schools.
TIME FOR A POP QUIZ
1. How does your body help protect you from the strong acids in vomit?
2. Why is throwing up mostly a good thing for your body?
3. How is your body sometimes tricked into throwing up?
4. Why do many people feel sick when somebody near them throws up?
5. What organ in your body determines when you will throw up? How?
LAST WEEK’S POP QUIZ ANSWERS
1. What is a contrail made of?
A contrail is made up of water vapor that has condensed into liquid form. The vapor is also frozen due to the temperatures in this part of the atmosphere.
2. All clouds can give clues to the coming weather. What type of cloud tends to match the clues from contrails? Why?
Cirrus clouds and contrails can often give similar clues because they form at the same layer of the atmosphere.
3. If you look up and see several contrails that go across the entire sky, what might you say about tomorrow’s weather?
The weather may be changing to bring in more clouds or precipitation.
4. When will a warm pocket of steam stop rising?
The steam will continue rising until the air pocket is no longer warmer than the surrounding air.
5. What will the steam from a smokestack look like if clouds are likely to form later that day?
The tower of steam will likely reach high into the air before flattening out or evaporating.
