Vestigial organs are viewed as organs with no real function. Often the appendix is viewed as a vestigial organ however it is not. It protects good bacteria in the gut, however, you can still live without it (S_J_Emerald).

Our jaw muscles are some of the most powerful muscles in our bodies. When all the muscles of the jaw work collectively they can close teeth with a force “as great as 55 pounds” on the incisors. The molars can get to “about 200 pounds” (Exciting_Clock2807).

The proportion of our vision that is sharp focus averages to around the size of a thumbnail at arm’s length. The visual cortex fills in the rest of the blanks. Pretty impressive! (misterway).

Tiny cilia spin in a specific direction which is very important as a baby is developing in the womb. If they are to spin in the opposite direction it will cause organs to change to the opposite side of the body. Some twins can even have mirrored organs (gurgleslurp).

Our hyoid bone is a U-shaped bone that sits at the root of our tongue in the front of the neck and between the lower jaw. Its main purpose is to serve as an attachment structure for the tongue. However, the hyoid bone is not attached to any of the other bones in the body (emzirek).

During delivery, babies can break their collarbone. This happens pretty often and they recover rather quickly. But if you did break your collarbone as a baby you may have a callus on your collarbone where the fracture grew back together (jaelIlii).

For some reason, if you cut off the fingertip of a child under 11 it can effectively regenerate in 100% of cases. There is no reason why this can happen or as to why only children under 11. Full regeneration also occurs in many animals (josiahpapaya).

One tiny knee bone that was once lost in humans is slowly making a comeback. That tiny knee bone is called the fabella. Back in 1918, the fabella was only found in 11% of the population. In 2018, that percentage rose to 39% of people (Cruithne).

Growing a human isn’t the only thing a woman’s body grows while pregnant. Women also grow an entire organ called the placenta that provides oxygen and nutrients to the baby. The placenta also removes waste products from the baby’s blood (HeartKevinRose).

The act of splashing cold water on your face can trigger the mammalian diving reflex. Essentially, this optimizes respiration by circulating oxygen to the heart and brain. So splashing cold water on your face or leaving any part of the body in cold water for an amount of time can assist in calming you down (maybeeee_).

Our bodies are capable of great things and operate in the most fascinating ways. For example, our eyes have a completely separate immune system from the rest of our bodies. This means if our body’s immune system is compromised and it finds our eyes it will assume it’s foreign and can blind us (SlavicSquat1234).

Palatal tori is a bony growth in the roof of your mouth. Also known as torus palantinus which only occurs in 20 % of the US population. The “tori” is extra bones that are harmless growths (Alagane).

There are several muscles, ligaments, and tendons in our jaw. Specifically our temporomandibular joint. Pulling or straining a muscle is the most common TMJ problem (MissSara101).

Children’s kneecaps start to ossify which means turn from cartilage to bone between the ages of 2 to 6. A slow process that takes years. By ages 10 to 12 the kneecap is fully developed (Additional_Ad4880).

We lose thousands of skin cells that are replenished by fresh skin tissue instantly. Our bodies do a great job of getting rid of that skin which can total up to about 30% of body waste. Showering, sweating, and exfoliating are good ways to get rid of waste (insomniac_observer).

According to one cardiac anesthesiologist he reports that hearts smell like mushrooms. Another report they’ve only ever noticed a coppery smell. Even a veterinarian weighed in reporting that although human hearts may smell like mushrooms other mammalian hearts do not (littlepoot).

Have you ever wondered why your nose runs when you cry? It’s because the tear ducts in the corner of your eye connect your eyes with your nose. There is a continuous flow of tear liquid in our eyes to assist with keeping them clean and rinsing away any tiny dust particles. Often this passes down the tear duct unless there is an excessive production of tear liquid that surpasses its capacity which causes the eyes to overflow…which we know as crying (Bitchmom_6969, Dynein).

Ever wonder how in distress people get hulk strength? Turns out the brain is what regulates how strong your muscles are. If our leg muscles were to contract at maximum strength our femur could snap! Our bodies are capable of reaching incredible powers, however, it does come with a cost of potentially severe injuries. Luckily our brain most of the time keeps us weak (Andibular).

After experiencing a trauma your body sends your brain into a fight, flight or freeze. When you develop PTSD it isn’t just mental but physical too. The chemistry in your brain can send signals to your body that there is a threat. Which can lead to the immune system attacking parts of the body by mistake (ibiblio).

Our shoulders are not as simple as they seem. They are made up of various joints that help them function. There’s the glenohumeral joint which is the ball and socket, then there’s the acromioclavicular joint which is a plane joint, then there’s the sternoclavicular joint which doesn’t involve the shoulder blade, however, it does have the same muscles as the acromioclavicular joint around the same kind of region (c0b4lt_chl0ride).

If a liquid was supersaturated with oxygen in theory humans could potentially breathe it. Although it would not be easy due to the density of liquids. Realistically we would only last about 15 minutes before becoming too fatigued (Crackracket).

There is a common saying that we have two brains, one in our head and one in our stomach. Turns out our stomach is surrounded by nearly half a billion neurons. This is called our enteric nervous system and it controls our digestion, has memory, handles reflexes, and senses too (Hattix).

For the most part, children are very cute. However, x-rays of their mouths are nightmare fuel. On their x-ray, you’ll see two rows of teeth waiting to replace baby teeth (demonardvark).

On average our brains makeup about 2% of our body weight and use 20% of our caloric intake. In an interview with Time Ewan McNay who is an associate professor of psychology and behavioral neuroscience a the University of Albany states, our brain “runs exclusively on sugar and glucose, and strenuous cognitive activities require more glucose than simple ones.” This is why oftentimes when we are studying or doing a lot of thinking we can become hungry because our brain is consuming more energy.

Fainting at the sign of blood occurs when our body overreacts to the sight of blood or in circumstances of extreme emotional distress. This is called vasovagal syncope or neurocardiogenic syncope. Some theorize this developed as a survival mechanism similar to animals playing dead (shibapop).

To tear off someone’s ear only requires about 10 to 15 pounds of force. This is often taught as a self-defense technique for hand-to-hand combat. Although tearing the ear is more damaging another survival technique is slapping the ear which is extremely painful and can knock someone off their balance (02K30C1).

When we have bowel movements our heart rhythm momentarily changes. This is due to a vagus response. Which explains why Elvis died on the toilet. Because his heart was beating 200+ bpm the beat change induced myocardial infarction or otherwise known as a heart attack (MadameBurner).

Turns out the first swallow pattern we learn as babies isn’t correct. When babies swallow they push their whole tongue forward. This method is better for nursing, however, once we transition to solid foods the proper way is by pushing the tip of the tongue to the roof of our mouths instead to roll the food back (Shimerald).

Our spinal cord is the one that sends the muscle movement signals to your limbs. Most of our quick reflexes never even make it to our brain. For example, the quick withdraw of our hand when touching a hot stove (thundermuffin54).

Although tickling makes us laugh it isn’t a pleasurable sensation. Researchers in Germany in 2013 concluded that tickling triggers a part of the brain that is responsible for vocal and emotional responses named Rolandic Operculum. However, we can’t tickle ourselves because of our cerebellum which predicts the tickle and cancels out the sensation (neurosatsfx).

Our brains love stimulation and when it doesn’t get any it will make something up! Oftentimes these are the colors we see before falling asleep. There are also various classes of these “hallucinations“: closed eye visuals which happen when we leave our eyes closed for a long time, there’s hypnagogia which is generated by the onset of sleep, there’s prisoners cinema which happens by gazing into a dark place for an extended time, there’s ganzfeld effect which happens when all external stimuli are blocked and Charles Bonnet syndrome which happens when you lose your sight (NoCommunication7).

The average adult has around 22 feet or about 8 pounds of skin! To put that in perspective it would make for a nice rug or a conventional doorway is 21 square feet. About once every 35 days our skin regenerates itself which means by the time we reach 20 years of age we’ve cycled through skin approximately 200 times (angry_centipede).

All over the world people live and learn to thrive in “extreme” conditions. Over generations, they can not only learn how to adapt but their bodies do as well. People who take residence at higher elevations tend to develop larger lungs and various blood structures. As well as, Bajau people who live on the water spend a lot of their time free-diving because of this overtime their spleens became 50% larger to store more blood (localhelic0pter7).

As we’ve learned multiple times throughout this slide the human body’s design is quite purposeful and interesting. For example, there is an explanation of why it is rather easy to break our collar bone. It acts as a circuit breaker to stop the shock of impact and protect our spine (Hardboiledsoftshell).

If you’ve ever questioned why it feels weird when someone touches the inside of your belly button it is because the nerves go all the way to your spinal cord! These nerves rest on the same level that sends signals to your bladder. So if you’ve ever touched the inside of your belly button and felt like you had to pee this is why (purgingitall).

When we say “woooh” cold air comes out of our mouth but when we say “haah” our breath comes out warm. Sorcery? Not quite just aerodynamics and heat transfer mechanisms…so basically sorcery. Essentially our brain communicates to us that the faster airflow is colder (Marianmza).

The surface area of our lungs is pretty big as they are one of the largest organs in our bodies. Not only is the surface area the size as a tennis court but can also can be compared to the total length of the airways running through them is 1,500 miles. Which is equivalent to the distance from Chicago to Las Vegas (felipebsr).

Scars are held together by collagen and are constantly trying to heal themselves. Vitamin C helps to support this repair as well as other things. However, those who have scurvy or a vitamin C deficiency often see their scars reopen and become fresh wounds (misterway).

There is some severe drug-resistant epileptic syndrome that develops in young children and the only option they have discovered that stops the seizures is to completely remove a brain hemisphere. This surgery is called a hemispherectomy and is a highly invasive surgery that can entail complete removal or severing half of the brain. Once removed they will have a limp, blindness in one eye, very weak arm but with proper therapy and reeducation, the child can go on without a cognitive deficit (Matrozi).

We are more like chimpanzees than we think. On average, we have just as many hairs on our bodies as chimpanzees do! Our hairs do look a little different though as they are finer and shorter (Inner_Inspection6408).

You can grow a baby faster than a new toenail. In fact, it takes approximately 18 months for a toenail to fully grow back! A fingernail can take about 6 months (CurrentAttention3).

Many of us have experienced listening back to a recorded sound of our voice and being so uncomfortable we had to turn it off. But turns out there is a reason why we dislike the sound of it so much! When we talk we hear our voice as it travels through the air and comes back to our ears. As it passes through our skull it then goes through to our ear and then to “this bone conduction mechanism” which transmits low frequencies better than the air does. Our recorded voice is only the air transmitted sound this is what causes the discrepancy of what we think we sound like to reality (BlocterDocterFocter).

It seems almost too crazy of a statement that you could die sooner from sleep deprivation than a lack of food! But depending on your health level and body fat you could survive for months without food. It is estimated if you are sleep deprived you could die within 2 weeks (feliciates).

Though it may seem like Alzheimer’s disease is just a progressive loss of memory it is actually a physical substance that exists in the brain. Unfortunately, it is one that attacks the brain. If you were to look into the skull of someone with Alzheimer’s you would see a “sticky, fibrous, grey physical matter” slowly overtaking the brain (cccairooo).

While performing surgery doctors might have to take out some organs to get to where they need to be. But when it comes to putting them back rarely do they ever go back to the exact place they were found. But don’t worry our bodies just kind of move them back into the correct position over time. Depending on which organs were moved a sign of them moving back into their correct place is gas pains (IamaJarJar).

Even after the heart has stopped it takes our brain a moment to shut down as well. Some cases have shown brain activity continuing for 30 hours after the heart has stopped trying to make repairs to revive the body. Some cases even show EEG brain activity can continue for up to 72 hours (flamingphoenix9834).

Unfortunately, you read that right, you can poop out of your mouth. This is called fecal vomiting and it is a sign of a major health issue! This happens when there is a blockage in the small or large intestine and waste can’t go to its regular exit place. Other symptoms are abdominal pain, constipation, and dehydration which if left untreated could lead to death (DTownForever).

We, humans, have stripes, however, we can’t ordinarily see them. These stripes are called “Blaschko’s lines” developed along the paths of embryonic cell migration. These stripes take a U-shape down the front or a V-shape down the back. They appear wavy on our head and face while on our extremities it is said we have basic simple stripes (LadySygerrik).

Many of us are already aware that our eyes have blind spots. These blind spots are where the optic nerves connects to our retina. Because of these blind spots each eye sends data to our brain so it can fill in what’s missing. Click here to test yourself! (Windshards2)

Even against the animal kingdom humans have evolved to become the best runners on the planet. Even though cheetahs are the fastest land animal, humans can still outrun them when it comes to distance. This is because marathon runners train their endurance and because of this their bodies have evolved (Keinichn).

We have millions of old but tough cells covering our bodies for protection. However, they only stay for a bit, and then they flake off. It is said that every minute of the day we shed about 30,000 to 40,000 dead skin cells (ae1021). Which is about 9 pounds of cells per year!

National Geographic writes, “As you read this, you are glowing — weakly, faintly, but glowing nonetheless.” Turns out we are bioluminescent and glow in the dark! Although the light we emit is 1,000 times weaker than our eyes can see. Our glow is the strongest around the late afternoon near the lower part of our faces (-eDgAR-).

Although extremely delicate the eyeball is the quickest healing part of our body. If you were to cut your cornea you would be in great pain but since it doesn’t contain blood and only gets a supply of oxygen it is the fastest healing part of our bodies. It can repair in a mere 24-36 hours! (_Nugget_UwU)

To absorb fluids our body must warm them first. So when we drink a cup of ice-cold water our body burns more energy trying to warm up the water. This means we aren’t hydrating as quickly (Cordero_Biggs).

The human body can do some pretty amazing things. However, humans are one of the few species of mammals that don’t produce vitamin C. This is because of a lack of an enzyme. Most other mammals produce vitamin C in their liver (TexasPatrick).