11 Insane Features of Normal Human Anatomy
Sure, we’ve wowed you with medical oddities, but why should abnormal bodies get all the attention? The truth about the normal human body can be stranger than fiction. To prove it, here are 11 weird facts about the body you thought you knew.
1. Your Tongue
What does your tongue have in common with an octopus’ tentacle and an elephant’s trunk? All three are examples of a unique structure called the “muscular hydrostat,” a bundle of muscles that work without the assistance of bones. Like anything made mostly of water, the hydrostat has a constant volume, so when certain cells contract, the whole thing has to expand somewhere else. The result is a body part that is both strong and flexible. If your tongue were as big as an elephant’s trunk, it could uproot trees too.
2. Your Hyoid Bone
This wee, horseshoe-shaped bone will never appear in the song by James Weldon Johnson, as it’s connected to...no bones at all, in a meaningful sense; its job is independent of the rest of the skeleton. Also known as the lingual bone, the hyoid bone sits atop the larynx, providing an anchor for the muscles on the floor of the mouth, the tongue. Don’t worry: you’re not likely to break this bone, unless someone starts choking you to death. At that point, you’ve got bigger problems.
3. Your Philtrum
No, that little indent under your nose isn’t there to make it difficult to apply lipstick in the dark, but it doesn’t serve any other purpose either. The indent, called the philtrum, is just a residual reminder of your time in the womb: in utero, the two sides of your face develop independent of one another, then join at the middle. When the two sides fail to fuse properly, the result is a cleft palate, which occurs in about 1 of every 750 births. Ancient Romans found the philtrum erotic, and named that lipstick-thwarting dip in the upper lip “Cupid’s Bow.” In fact, the word philtrum comes from a Greek term meaning “love potion.”
4. Your Hair
People love tossing around hair facts. That old wives tale about it growing after you’re dead? A fun fallacy. After you die, your hair and nails don’t continue growing, but the skin retreats as it dehydrates, causing that creepy illusion of ghoulish growth.
In truth, hair is a weird combination of living and dead. The living hair follicle pushes out the hair, which is made up of different kinds of non-living yet protective cells made of keratin — the same keratin that's on your top (dead) layer of skin, and in your nails. When your hair turns grey, it means your pigment cells are dying. Yet another hairy reminder of your own mortality.
5. Your Nails
Ever notice how your toenails grow more slowly than your fingernails? That’s because there’s an evolutionary correlation between the length of your “terminal phalanges” (the outer-most bones in your toes and finger-tips) and the rate at which your nails grow. The tips of your toes are shorter than your fingertips, so your toenails don't grow as fast. In the same way, the nail on your middle finger will grow faster than the nail on your pinky. The seemingly random correlation has to do with the lessening necessity of claws through human evolution. If your fingernails are thick and grow quickly, ask yourself the question: “Should I be digging more?”
6. Your Bioluminescence
Fireflies and jellyfish glow, but humans? Believe it. The phenomenon is a natural byproduct of the metabolic process, and scientists have long been aware of the presence of bioluminescence in most living creatures. But it wasn’t until 2009, when a team of Japanese researchers developed a camera 1000 times more sensitive than the human eye, that human bioluminescence was captured on film. The light show apparently works on a 24-hour cycle — brightest in the late afternoon and on the cheeks, forehead and neck. Next time someone tells you “you’re glowing,” you can take it literally.
7. Your Walking Proteins
Of the microscopic menagerie that is your cell biology, the most bizarre member is perhaps the kinesin protein, a “motor” protein whose job it is to deliver important molecules to their necessary cellular destinations. What’s most remarkable is the kinesin’s mode of transportation: It “walks” along its micro-pathway using two structures at its base commonly referred to as “feet.” Though scientists disagree as to exactly how these feet were “made for walking,” there’s no denying that the mode of transportation closely resembles that of the humans they assist.
8. Your Sonic Hedgehog
What’s more complex than cell biology? Cell biology in your infinitely complex brain. In 1993, scientists discovered a protein in the hippocampus instrumental in developing a variety of neural traits. Isolated in fruit flies, the protein causes spines to grow on the back, so the scientists named it “Sonic” after the spiny Sega Genesis character. Similar proteins are named desert hedgehog and Indian hedgehog. Who says scientists don’t have fun?
9. Your Liver
The lumpy, lobey, unwieldy liver gets a bad rap, but if you didn’t have it in there cleaning out your system, you’d be looking pretty bad yourself. Lucky for you, the liver is perhaps the most resilient of the major organs: it can regenerate from only 25% of its tissue mass. You wouldn’t vote it the cutest kid in school, but “Most Likely to Succeed”? Maybe.
10. Your Vomeronasal Organ
There are important organs, and there are ones just along for the ride. As far as useless leftover body parts, you’ve probably heard about the tailbone, the appendix, even the little toe (wee wee wee all the way home). But you may not have heard of the “vomeronasal organ,” located unglamorously inside the nose.
Back in the day, the little guy used to aid in detecting subtle airborne information, most importantly, pheromones from a member of the opposite sex. In the age of modern man, the vomeronasal organ doesn’t appear to be doing much -- it doesn’t even have nerves connecting it to the brain. Still, scientists continue to argue about the potential chemical messages it might be sending, titillating that part of us that is still animal.
11. Your Sexy Bits
And speaking of pheromones and vestigial organs...
Men and women have more in common “down there” then you might think. Because the sex organs of a fetus don’t develop until about five months into development, males and females have remnants of the opposite sexual organs — and some are more useful than others. While the penis is basically an enlarged version of a lady’s clitoris, the male remnant of the lower vagina is less useful. Called the prostatic utricle (Latin for “pouch of the prostate”), the little-discussed fleshy sac just kind of hangs out near the prostate gland, leading nowhere. In the 1800s, the structure was more commonly called the vagina masculina, which requires no translation.