Disclaimer: Some of the responses below include discussions of human anatomy that may be disturbing for some readers.
1.
“Some people are walking around with three or more kidneys because when you get a transplant, the old ones are often left in place unless it’s medically necessary to remove them.”
2.
“Your brain can’t actually feel pain. That’s why surgeons can perform brain surgery on awake patients. You can feel pain in your skin, skull, and meninges, but the organ that interprets pain itself feels none. It’s unsettling to realize the thing that screams “ouch” can’t experience it at all.”
– DoldyDon
3.
“When you twist your wrist, your forearm bones overlap. It’s biomechanically normal, but kind of gross to see in a simulation.”
4.
“The ovaries aren’t physically connected to the fallopian tubes. Eggs are released into the tubes, not passed through a direct connection. This also means that certain other things (👀) that may enter the fallopian tubes can ultimately swim out the ends and end up floating around in the abdominal cavity.”
5.
“Fun fact about your intestines: after a doctor takes them out during surgery, they’re simply placed back inside. Your intestines will reorient themselves into the correct position on their own.”
6.
“About 5% of our brain activity is conscious, and 95% is unconscious. That’s not the creepy part. The creepy part is that studies have shown the unconscious part of our brain can make a decision several seconds before the conscious part thinks it’s made a choice and then retroactively justify the “why” with conscious thoughts afterward.”
7.
“You can poop out of your mouth.”
10.
“Colostomies can get STDs. And yes, in the way you’re thinking.”
12.
“Tiny, eight-legged, wormlike mites called Demodex—which are actually arachnids related to spiders—live in and under our eyebrows.”
13.
“I have three 🙂 1. Ribs can regrow. This is something doctors have to watch for when ribs are removed for medical reasons. If a small portion is left behind on the rib cage, it can act as a bud and start forming new bone.”
14.
“Your pinky fingers are incredibly important; without them, your overall grip strength decreases by about 33%.”
15.
“You can be internally decapitated. The neck breaks, and your head is literally only connected by soft tissue.”
16.
“Last year, my sister had a teratoma, and learning what that meant still makes my skin crawl. It wasn’t just a tumor, but a mass that had grown hair, teeth, and fragments of fully formed tissue, as if parts of a body had tried to assemble themselves in the wrong place. Teratomas come from stem cells that don’t know when to stop differentiating, so they can form skin, bone, muscle, and sometimes even structures that look disturbingly close to eyes. The realization that something inside a human body can quietly grow the building blocks of life—completely out of control—is deeply unsettling.”
17.
“There are a few people born with all their organ asymmetries on the opposite side (pancreas, liver, aorta position, etc.). This isn’t creepy until you try to diagnose appendicitis.”
18.
“When your head hurts due to dehydration, it’s actually because your brain is shrinking slightly.”
– rlyd3ad
19.
“I literally just found out that sometimes after getting hit in the nose, instead of bleeding, you’ll have watery fluid pouring out. But it isn’t snot—it’s cerebrospinal fluid leaking out, which can lead to meningitis and possibly be fatal. So yeah, that’s a new fear I’ve unlocked for the rest of my life.”
20.
“Your bladder is connected to your belly button. There’s a condition that can cause your belly button to “open” and leak urine.”
21.
“A fertilized egg cell can, in rare cases, develop into cancer rather than a normal pregnancy. This is known as choriocarcinoma.”
– alyyana
22.
“Endometriosis can occur in almost any part of the female body. Removing the ovaries doesn’t eliminate it, and the tissue can even produce its own hormones, meaning pain and other symptoms can still continue.”
23.
“I never realized that children have their adult teeth positioned above their baby teeth. I once saw a child’s skull, and it really freaked me out.”
24.
“Your inner eye, particularly the retina, is an immune-privileged site, meaning it’s hidden from your overall immune system. If your immune system were to “discover” certain elements of your eye, it could trigger an autoimmune attack on these “foreign” tissues and potentially cause complete blindness.”
– Arch3591
25.
“There’s a possibility that a woman’s immune system can reject a man’s sperm, making her unable to get pregnant by that specific partner even when both are otherwise fertile. So there’s a chance a couple can’t have children simply because of this random incompatibility, and there isn’t much that can be done about it.”
Okay, that’s officially enough internet for today, and I would like to delete several of these facts from my brain. Let me know in the comments which one of these caught you the MOST off guard!
Text has been edited for length and clarity.