Human bodies are weird and gross and wonderful things that more people should learn about considering, ya know, we're all in one.
So when one reddit user asked:
People showed up in droves to share their knowledge. Things were certainly interesting, but we honestly had no idea that our bodies were simultaneously independent machines capable of functioning in parameters we have no business being in (and doing so without our input most of the time) - and also really, really, reeeeaaaally crap design.
The acid in your stomach could burn your skin! I always thought that was pretty interesting, and reminds me of the scene in Alien, where the alien blood burns everything.
Which is why vomit feels so boiling hot
This is also why you produce a lot of saliva before vomiting - to protect the teeth and mouth from the acid
Intestines Work Themselves Outanimation wiggle GIF by xponentialdesign Giphy
Your intestines are constantly wriggling like worms or snakes and arrange themselves how they want to be. After abdominal surgery, doctors just stuff em back in and let them sort themselves out.
To be specific, they don't stuff it back willy nilly. There are some general rules, like this section goes here, and that one there. But the loops within those sections will arrange themselves since your intestines are attached to the back of your abdominal cavity through mesentery.
Looking Out For Mom
When pregnant, if a mother suffers a heart attack or other large physiological issue, the fetus will release a swarm of stem cells that move to the affected area, greatly helping in survival and healing.
Also the baby leaves a bit of its DNA in its mother which can manipulate her body for decades. It's called microchimerism.
Source: smithsonianmag.com September 2 2015, article by Viviane Callier.
Besides the genitalia, there are several parts in your body that can go through processes that can be classified as an erection, like nipples.
goosebumps are called piloerection and is just a bunch of erections in your hair follicles.
The tissues inside my right nostril are erect so much it is rare that I can breathe through that side. (It is a cleaning mechanism for the nose...just goes a bit haywire for me)
The clitoris also has erectile tissue. I know it's genitalia but a lot of people don't know that.
Hack Your Urine Stream
If you tickle just above your butt crack while you're peeing, it makes you pee more.
There's an explanation for this! It's called the anogenital reflex. Many baby animals (puppies, kittens, squirrels, etc.) rely on a parent stimulating the newborn's genitals (typically by licking), since they can't pee on their own yet. Orphaned animals in the care of humans require stimulation of the genitals with a warm wet Q-tip or something to get the job done. - tmlp59
Hidden Mickeysthrough the years kiss GIF by Mickey Mouse Giphy
You can determine the sex of a skeleton by looking at the pelvis and seeing if the pelvis looks like a Mickey Mouse head (female) or a reindeer head (male). It's funny, but it works surprisingly well in some cases.
It doesn't always work a 100% for prepubescent skeletons and pelvises that have in between markers, but it's still a fun trick.
So Much Extra
The laryngeal nerve starts in your brain and goes down into your larynx and controls what the larynx does (breathing, swallowing, voice box, etc.). So you'd think it's about 5-6 inches long, right?
Instead, the nerve travels down your neck, past your shoulders, wraps around an artery close to your heart, then travels back up to your larynx, adding and extra 15-20 inches of unnecessary length.
This same nerve is also present in giraffes, and also loops around the giraffe's heart as shown in this giraffe dissection video. This 2m long, doubled-up nerve's beginning and end points are a hands' width apart. There's so much extra and it's all useless.
Eyeballs Are Weird
Our eyes are super cool. You would think they all of the blood vessels going into the eye would be behind the photoreceptors, right? So that the blood vessels don't interfere with the light we're seeing? Well, it turns out, that's not the case. That's why we have a blind spot. Its where the blood vessels enter through the back of the eye, and then they spread out around the inside of the eye. So there's a whole bunch of blood vessels in the inside of our eyeballs, and that means that as light enters the eye through the pupil, a shadow of the blood vessels gets cast onto the photoreceptors in the back of the eye. Normally, our brain does a great job of photoshopping these out. But under the other conditions, it's actually possible to see those blood vessels.
But it gets even weirder. The blood vessels in the eye are so incredibly tiny that blood actually flows through them in a single-file line, one blood cell at a time. The plasma and the red blood cells, which make up the vast majority of blood, pass by completely invisible. But the other 1% of our blood, the white blood cells, can on rare occasions actually be seen! Once again, it requires pretty specific circumstances, most importantly a uniform field of blue light. And it just so happens that the sky on a clear day is the perfect shade of blue to see the blue field entoptic phenomenon.
If you were to stretch out the entire surface area of your lungs, they would cover a tennis court.
I found this out because I was searching Google for the typical size of a tennis court and one of the suggested searches was something like "are your lungs as big as a tennis court?" and I was extremely confused for a moment.
Human breast milk adapts it's nutritious content to fit the need of the offspring. Baby lacks iron? Next dose of milk will contain more iron. It's amazing.
Breast milk is SO cool!! There's a reason why it's called liquid gold!
More fun facts:
1- breast milk can be dripped into babies eye/ear/nose to treat infections (as mentioned by someone below, it works best as an anti-inflammatory, which can help! Also, it's more of a preventative than a cure.)
2- breast milk does change depending on babies needs and as they grow
3- breast milk contents differ depending on babies gender
5- it works on mild eczema!
6- the components of breast milk could lead to treatment for cancers! possibilities still under trial
7- it's "made" out of the mother's blood". "Milk is made inside glands from the blood stream. Breast milk is NOT made from the mother's stomach contents. The foods mom eats are broken down in the digestive system. Blood reaches the milk glands where it delivers carbohydrates, nutrients, white blood cells, enzymes, pro- and pre-biotics water, fat, and proteins into the gland." link!
8- mothers can detect issues with the baby through all of that kissing, which tells her body what to produce (like more antibodies etc) whoa!
Edit: you should of course always take your little to a doctor with any issues. These are "fun facts" guys! They should not replace any medical advice from a doctor. As I quoted somewhere below "However, the use of breast milk in treatment is not applicable in all cases. It should rather serve as complementary therapy, and not the only mode of treatment. At our present level of knowledge, non-nutritional uses of breast milk are certainly better suited to prevention than to a medicated process. "
Want to "know" more? Never miss another big, odd, funny, or heartbreaking moment again. Sign up for the Knowable newsletter here.