62 Weird Medical Facts That Turned Out To Be True

The "need to breathe" you feel when holding you breath is from an overabundance of CO2 in your lungs, not a lack of oxygen. In fact, your body has no way to tell you you're not getting enough oxygen. Hypoxia is a thing, yes, but your ability to think and act is heavily impacted by that point.

tokke:

That's why hyperventilating can be dangerous. It removes to much CO2 from your blood, but doesn't provide enough oxygen to balance out. So after hyperventilating, if you would hold your breath you wouldn't feel the need to breath until it might be to late. One of the dangers if you are freediving.

Your lower eye lids have a little visible hole on the inside area that touches the bottom of the eye. This hole drains directly into the sinuses, and is the reason why sometimes when you messy cry your nose runs too.

You can in fact die from literally drinking too much water in a short amount of time. Its called **Hyponatremia or water intoxication.** It usually affects high or extreme performance athletes who are unaware that they've taken in too much during their race (like triathlons etc).

The mitochondria (powerhouse of the cell) are almost certainly other organisms that integrated into our own cells during our evolutionary history, and have their own genome.

megabeano:

And isn't mitochondrial dna only passed down from mothers? So we can trace matrilineal geneology very accurately by looking at that dna instead of what's in your nuclei. It would be very very similar since I assume the only differences would come from mutations.

OP:

Correct; s***m have mitochondria, but very little mitochondrial DNA and what mtDNA it does have is largely degraded after fertilization, meaning that mtDNA is solely inherited from the egg.

mS0hungry:

Is this related to the shrinkage and potential loss of the Y-chromosome?

OP:

Not really. Remember that s***m are roughly 50% X and 50% Y chromosomes, so anything Y-chromosome specific wouldn't be related. Current theory is that because the mitochondria in s***m are specialized to provide movement for the s***m and are relatively unprotected from outside forces, there would be a higher risk of mtDNA damage, and therefore it was evolutionarily advantageous for the s***m's mtDNA to degrade rapidly after fertilization.

Your lung can just up and collapse without warning for no discernable reason. It's called a spontaneous pneumothorax.

No one actually knows how Lithium works as a medication...just that it does something sometimes for some people.

A “Bogota Bag”.

A sterile plastic bag, from leftover medical supplies, can be sewn into human skin to create a temporary “skin” around abdominal wounds.

EMDR. The fact that moving your eyes side to side a few times can reset me after a traumatic incident feels like a cheat code.

You're somewhere between 3-7% virus DNA.

No, not 7% of your mass is virus, but your living bodily DNA is that of a virus.

Broken heart syndrome.

You can live without a stomach, spleen, or gallbladder.

The brain has no pain receptors, this is how awake brain surgery is possible for certain tumors in very eloquent regions.

In people with auto brewery syndrome the body produces its own alcohol.

You have invisible buttcheek swirls and stripes on your skin. They're called Blaschko Lines. They're believed to be the pathing cells took when they divide and grow into the skin you're in now. Certain skin conditions follow these pathways on you body.

Sitis Inversus is a rare medical condition where your internal organs are entirely mirrored. It presents no issues whatsoever until trying to diagnose something. For example, the telltale sign of appendicitis is pain in the lower right. Someone with sitis Inversus will have their appendix in the lower right, which is usually how it's discovered.

Mice and giraffes have the same amount of vertebrae in their necks.

If you apply pressure to your eyeball, it can slow your heart rate. In extreme cases, this can cause the heart to stop (asystole). 

The oculocardiac reflex is mediated by the ophthalmic branch of the trigeminal nerve via ciliary ganglia and the vagus nerve.

Another one: While moving your eyes, you are blind, and your brain compensates so you don't notice.

It's called saccadic masking and you can easily try it by looking at yourself in the mirror, looking at your eyes back and forth, and it will look like your eyes don't move. To compare with what it actually looks like, ask someone else to look at your eyes in the same way.

Evil bonus: I once convinced my little sister for a brief time that she was a clone and not a real human by exploting this. I told her she could not see her eyes moving in the mirror because they where actually cameras, not real eyes.

Bones are naturally wet.

Half of all doctors were below average in medical school.