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Humans – Why Are We So Gross?

Our bodies, all in all, are pretty impressive. We’ve got big brains, mighty muscles and intricate insides. Human bodies are remarkable, finely tuned machines. Unfortunately these machines have a lot of by-products. We make sick, snot, pus and poop. There are no two ways about it, these things are pretty disgusting. But what are they, what are they made from and why have our bodies evolved to make so much unpleasant stuff?

Read on if you have a strong stomach and you’re not currently eating. This isn’t one for the squeamish.

What is Sick Made Out Of?

VomittingSick is just undigested food and liquid from your stomach mixed with gastric acid. The gastric acid is what makes throwing up hurt. It is a mix of HCl and KCl that the stomach uses to kill microbes present in food and has a low pH (around pH1). Food is churned around in the stomach for a bit with a few digestive enzymes and the gastric acid. Once the food is nice and slurry-like it passes into the intestines for absorption.  When you’re sick, whatever hasn’t made it to the intestine does a reverse anti-gravity manoeuvre and comes back up. Lovely stuff.

 

What is Snot Made Out Of?

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Snot is infected mucus. Mucus is constantly secreted by the delightfully named Goblet cells that adorn your airways. Mucus is largely made out of proteins with massive chains of sugar attached. These molecules cling on to water, which gives mucus its slimy consistency. Most of the time mucus is a good thing, trapping dust and microbes. The cells of the airways are covered in hair-like structures that can then waft the dust-microbe-mucus combo out of the airways and down into the stomach where it can be digested.

This all goes a bit awry during a cold when the cells in your airways get infected with cold viruses and the mucus becomes snot. Your immune system declares war on the virus but unfortunately during the battles, there are a few casualties to your own cells. Some of these are white blood cells that can explode to release chemicals, which kill invading nasties. One of the thing that spills out of these exploding cells is a green coloured anti-bacterial enzyme called MPO. So green snot isn’t so bad, it just means your white blood cells are doing their job and fighting infection.

What is Pus Made Out Of?

pus 2Pus isn’t too dissimilar to snot as it’s made out of a lot of debris from battles between the immune system and infection. Pus is essentially the remnants of all the white blood cells that have rushed to a site of infection and died fighting the invading microbes. Pus isn’t harmful, it’s a sign your body has been fighting infection the way it should and eventually the body will clear pus from sites that were infected. If pus doesn’t clear, it may be a sign your body is struggling to fight an infection.

What is Poop Made Out Of?

Yep, the grossest of all gross things. We all know what poop is, but what is it actually made from? Well, unsurprisingly undigested food makes up a large proportion. Dietary fibre – the stuff that keeps you regular – is the stuff you can’t digest and gives your poop a bit of form. So that’s good. There’s also a LOT of bacteria in there, which along with methane, causes the smell. It’s brown because of bile, which is a yellowing-green substance secreted by the gallbladder to help digest fat. When bile passes through the digestive system it changes colour and turns brown. The gallbladder is situated inside the liver, so if the liver gets swollen and inflamed it can block the bile duct and this results in poop that is white as a sheet. So if your poop looks like it’s seen a ghost, I suggest you see a doctor.

So there you have it – that is why human beings are gross.  It’s quite possible we’ve evolved to find these things disgusting as a way to avoid illness and infections.  Whatever the reason we find them off-putting, they are all just part of being human.

Congratulations if you made it the whole way through the post – you’re made of strong stuff.

Post by Liz Granger

Twitter: @Bio_Fluff

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3 Responses to Humans – Why Are We So Gross?

  1. Tsekouras says:

    All those “by-products” are quite natural to happen. I mean, bacteria wont politely ask humans whether they want this “by-products” or not. They have to take place for our sake, otherwise we would be all dead. Now, the fact that WE find it disgusting is due to our social rules. Howver, it is irrelevant for the nature what we find disgusting or not. Bacteria and viruses do not care about that. We, also, should not be concerned about that. More importantly, I do not see the reason why we just named them disgusting. May be we should change our social rules.

  2. Randall McKay says:

    I think it’s pretty cool there are all these living things alive inside of me that are making all these decisions like to clean up cuts, fight of diseases and stuff. Because for sure, I couldn’t remember to do all the little things that my insides, and outsides, do if they didn’t do them by themselves. It also feels kind weird to be talking about myself in the fourth person.

  3. Al says:

    Methane doesn’t have an odor. Try again.

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