The eyeball is the fastest healing part of your body.

Our brains make up, on average, around 2% of our body weight but consume 20% of our caloric intake

Your brain regulates how strong your muscles are. If your leg muscles were to contract at full strength, they would snap your femur.Its why people in emergencies on adrenaline can lift cars off children. Your body is capable of great strength, but it could also severely damage you, so your brain keeps you a weak, soft bag of jelly.

Humans have, on average, just as many hairs on their body as chimpanzees, human hair is just a lot shorter and finer.

You hate the sound of your recorded voice because it's missing the low frequency you're used to hearing.When you talk, you hear your voice as it goes to the air and back to you ear. It also goes through your skull to your ear, and this bone conduction mechanism transmits the low frequencies better than air does.Your recorded voice only has the air transmitted sound. That causes the dissonance between what you think your voice sounds like, and what it really does. It's also why your voice will (almost) always be higher pitch than you think.

When doing surgery where the doctors have to take out some organs, when placing them back, they don't have to be put back In the exact position there meant to be, your body kind of just, moves the organs into the correct position after the surgery

People who live in "extreme" conditions for generations adapt in extreme ways. For example people that live in high elevations often have larger lungs and different blood makeup. Or my favorite is the Bajau people that live on the water and spend a lot of their time diving, their spleens have become 50% larger in order to store more blood.

The heart smells like mushrooms.Source: I’m a cardiac anesthesiologist

The reason it's so easy to break your collar bone is because its designed to break.The way it was explained to me is that its like a circuit breaker. It breaks there to stop the shock of impact getting to your spine

The surface area of the lungs is about the same size as a tennis court

When you cry and your nose becomes runny, it's actually your tears.

You can grow a new human being faster than most missing toenails can grow back

Your brain continues to try to revive the body long after the heart has stopped. In some cases 30 hours later there has been found brain activity trying to make repairs to bring the body back. This is used to indicate time of death in murder victims.

Your eyes have a separate immune system from the rest of your body and in a lot of occasions if your body's immune system finds your eyes, they will assume they are a foreign body and blind you.

Humans are bioluminescent and glow in the dark, but the light that we emit is 1,000 times weaker than our human eyes are able to pick up.

Humans have stripes, we just normally can’t see them. They’re called Blaschko’s lines and form along the paths of embryonic cell migration. The stripes are sort of U-shaped down our front, V-shaped on our back, wavy on the head and face and we have basic, simple stripes on our extremities.

Every minute you shed over 30,000 dead skin cells off your body

Synovial joint fluid is the most frictionless stuff on the planet (unless they've synthetic'ed something up that recently.)

It's possible to pull a jaw muscle while yawning. I found this out the hard way at work one day.

Humans are one of a few species of mammal that oddly don't produce their own vitamin C due to lack of a certain enzyme. Other mammalian species who exhibit this mutation are those contained in the main primate suborder Haplorhinni (monkeys, apes, tarsiers), as well as bats, capybaras, and guinea pigs.All other mammals produce vitamin C in the liver.

The human body typically only uses 30% of its muscle’s strength. The only times where your body will activate full power is when it’s life or death. The cost of full muscle power is torn muscles, broken bone, stress, and in some cases, lacerations.

You will sooner die from lack of sleep than lack of food.You can live, depending on your current body fat and health level, for months without food. Estimates are you that you will die for lack of sleep within 2 weeks

Human eggs are small but big enough to be visible to the human eye

39% of people have an extra bone in their knee. 100 years ago only 11% of people had this bone.

It only takes about 15 pounds of force to rip off a human ear

Some women can feel the exact moment an egg is released from the ovary during ovulation. Feels like a little pop just on one side. Pretty neat

Jaw muscles are the strongest in the human body

You can poop out of your mouth if your intestines get backed up enough. It's like vomit, doesn't look like actual poop per se, but it's still disgusting.

If you faint at the sight of your own blood you may have an oversensitive vasovagal response. The theory is that this developed as a survival mechanism, kind of like an opposum playing dead.

You can live "normally" with half your brain. In some severe drug resistant epileptic syndrom in young kids, the only option to stop the seizures is to remove a complete brain hemisphere.After a while, with proper reeducation and all, the children can go on to have a normal life without cognitive deficit. They will have a limping, blindness from one eye and a very weark arm but can lead a normal life and not end up cognitively impaired.One of the earliest sign of alzheimer's disease, before the memory loss, could be the loss of the sense of smell. It's also the case with Parkinson disease.Our brain looks wrinkled because it is actually "folded" inside our skull in order to fit a maximum of surface and thus neurons & cell communications. Some animals like rodents have a completely smooth brain.

X-rays of childrens mouths are nightmare fuel. The second set of teeth to replace baby teeth are already grown and lodged in their skulls. So you'll see two rows of teeth and its freaky looking. They don't grow in when the old ones fall out, they are already loaded in the chamber waiting to get launched.

There's a "right" and a "wrong" way to swallow and the first swallow pattern you learn isn't the right one! Babies swallow by pushing their whole tongue forward (since it's better for nursing). However, as you transition to solid foods, you are supposed to change to a swallow where you put the tip of your tongue on the roof of your mouth and roll the food back. Not everyone does, and those that don't are more likely to choke, eat too fast, develop dental problems, and some develop a lisp or distorted sounds as they learn to talk!

Your stomach is surrounded by more brain cells (half a billion neurons) than the brain of a cat contains in total.It's your enteric nervous system. It controls digestion, operates autonomously, has its own memory, can handle its own reflexes, it has its own senses even.It's thought to have come about because of the blood-brain barrier and the main brain being locked away in the skull, a spinal column and nerves away from the critical action of nutrition.

There are tiny cilia that spin in a certain direction. If they spin in the opposite direction while you're developing in the womb early on, that is how you get organs transposed onto the opposite side of your body.

In theory humans could breathe a liquid if it was super saturated with oxygen. It wouldn't be easy because the density of liquid being so much higher than air so after 15 mins or so you would be too fatigued to continue breathing.The hardest part is getting all the liquid out of the lungs so the person doesn't get pneumonia

The average adult has 22 square feet of skin. Perfect size for a nice rug.

The hyoid bone is a bone not attached to any other bones in the human body and is only considered the anchor of the tongue

When you get conditioned to physical activity, your circulatory system adapts -- more blood, more vessels, more blood cells. But your lungs really don't. This is because no matter how much blood your heart is able to deliver to your lungs, the lungs still have no problem oxygenating it. This is why your oxygen saturation doesn't drop during exercise (unless you have a heart defect.)