Ever wondered about how the human body actually works? It’s a series of parts, interconnected, each seamlessly conducting a function that keeps you, well, alive. Think of each part as a specialist! But what if there was more to it all? What if our bodies were capable of doing such incredible things, that it was surprising? Whether you’re a medical professional, a pre-med student, or just a curious person, these 15 amazing facts about the human body may shock you:

#1 The Largest Bone in the Human Body is the Femur

It supports 30 times the weight of the person’s body, so if you weigh 115, your femur can support 3,450 lbs. That means it’s even stronger than steel!

That explains why it’s never your thighs that hurt, it’s your knees. The more you weigh, the more pressure your knees are under, potentially causing pain.

So remember, even if your femur can support you, the goal should be to reduce stress on your knees.

#2 In An Adult Human, 25% of Bones Are In the Feet

Feet are so intricate, they have 26 bones, 33 joints, 107 ligaments and 19 muscles and tendons. No wonder 75% of Americans experience foot problems at one time or another. It’s rather inevitable, since a quarter of all of the bones in your body are located right there.

Kind of dangerous, it seems like. It’s not exactly the strongest, or even most padded part of your body. Why the foot, of all places? Because that’s where your balance comes from.

#3 The Gluteus Maximus Is the Body’s Largest Muscle

That’s right, your butt is the biggest muscle you have. Contrary to popular belief, it’s not just fat or cartilage. It’s not all soft back there. That’s why you can shape it how you want through exercise.

Think yours is flat? Do squats, hit the gym, and watch it lift and shape up. It’s possible and doesn’t require surgery. Step away from the tabloids!

Think it’s too big? Well, there’s bound to be something you can do!

#4 Nose And Ears Never Stop Growing

We’ve all heard of this one, but it’s actually a myth! It’s not exactly growing, but more like sagging.

Sounds terrifying, right?

Turns out, as you age, gravity causes the cartilage to break down and sag, creating the illusion of growth. It’s not too noticeable in your twenties, thirties, even your forties and fifties, but sixties? You can see it a bit.

That means if you live to see your 90’s, you’re in for a treat!

#5 The Little Finger Makes Up Over 50% of Your Hand’s Strength

The middle finger, index finger and the thumb provide dexterity, but it’s the pinky that keeps your hands strong. It deserves more credit!

Here’s how it works: your other fingers are more about mobility, and the ability to grab things and go about your life. The pinky, on the other hand, is on the end, making your hands more adaptable and capable.

Without our pinkies, we wouldn’t be able to do a lot of things that require a good grip and strength.

#6 Your DNA Is Super Long

If uncoiled, the DNA in all the cells in your body would stretch 10 billion miles, the same distance from Earth to Pluto and back.

Although Pluto is no longer considered a planet, it’s still a decent distance away. Part of the solar system, it’s a whopping 4.67 billion miles from planet Earth.

So if your DNA is that long, it means that the DNA in all your cells put together would be about twice the diameter of the Solar System.

#7 There’s More Bacteria In Your Mouth Than You Think

There’s more bacteria in there than there are people in the world! That’s about 100 billion bacteria in your mouth at any given time. Gross!

That means when you kiss your beloved, you’re actually swapping quite a bit of bacteria. Understatement, for sure.

The good news is nothing can happen unless one of you is sick. So don’t kiss if you have a cold! Spare your partner the grief of coughing, sneezing and having a fever.

#8 For An Adult Human, Taking One Step Uses Up to 200 Muscles

That’s a lot of work, no wonder you can burn quite a few calories just by walking! You burn one calorie for every 20 steps taken actually. So if you need to burn 1500 calories, you’d be looking to take 30,000 steps, or 15 miles.

The thing most people don’t understand, however, is that the body needs you to burn a little more than that in a day. The average woman needs to eat 1800 to 2000 calories per day to maintain her weight, and men need roughly 2500. If you burn less calories than that, you’re actually gaining weight.

#9 The Human Skeleton Renews Itself Completely Every 10 Years

Whoa, right? This is possible because the body’s cells replace themselves every 7-10 years. They die, get replaced, and then cell renewal happens in sections in the body. Sometimes it’s your feet, other times it’s your hands or your legs, and so on.

Head-to-toe changes take a decade to happen though. It doesn’t happen all at once, it’s what happens after a decade of sectional renewal. That means when you hit the big 30 or 40, you’re not just celebrating a new decade, but a new skeleton to match.

#10 Your Fingerprints Aren’t the Only Unique Thing

That’s right, not just your fingerprints. Your tongue also has a unique print. No two are the same. Why this is, well, no one has any real clue. Same goes with fingerprints. It’s just something that happens.

But it does come in handy. Having traits that are uniquely our own and no one else’s makes it possible for forensics to catch criminals. So don’t lick things if you’re committing a crime (don’t commit a crime)!

#11 Your Feet Have 500,000 Sweat Glands

And produce about a pint of sweat per day. Which is apparently normal! That’s why when you’ve been exercising, and take off your shoes and socks, they’re slightly damp sometimes.

It’s normal and perfectly safe as long as you are careful not to reuse socks, or consistently wear closed shoes. Walking around barefoot is good for your feet and let’s them breathe from time to time.

If you sweat more though, you may have hyperhidrosis, a genetic condition where you sweat throughout the day, regardless of temperature or nerves.

#12 There’s A Ton of Nerve Cells In the Brain

So many, in fact, that it would take almost 3,000 years to count them. Several generations after you would have to sit there and count, count, count away just to count the cells in your brain.

And that wouldn’t even work, because once dead, your nerves go with it.

Why are there so many nerve cells in there? Think of your brain as a main hub. It controls absolutely everything in your body. How it works, when it does this or that. It’s the leader, and as such, it needs to have different transmitters doing different things at all times.

#13 An adult who weighs 150 pounds has a skeleton that weighs about 21 pounds

That’s the equivalent of a road bike! Good to know that technically, those 21 lbs. aren’t excess fat or anything, right? That same 150 lb. person would actually weigh 129 without the skeleton.

That means the skeleton weight roughly 7 lb. for every 50 lb. of body weight. Someone who weighs 180 lb. would have a 25.2 lb. skeleton.

The bigger the person, the bigger the skeleton, which makes sense. It needs to keep you upright.

#14 The Fastest Muscles Are the Ones That Make the Eyes Blink

They contract in less than one-hundredth of a second. And in one day you can blink about 11,500 times. That means they are not only the fastest muscles in the human body, they’re also the most hard working.

Even if you walk around quite a bit, and lead an active lifestyle, you’re still blinking at a faster rate than you are just moving around. It’s what keeps your eyes moist and irritant free.

The unfortunate thing is that because it’s such a minor movement, it’s not high in calorie burning. It’s not enough to affect weight or calorie burning.

#15 Your Skin Weighs 12 lbs.

So add up the clothes you’re wearing, plus heavy boots and an overcoat, and that’s how much it weighs.

Now that’s just crazy.

That’s why whenever you have to wear that heavy coat and boots, you wind up feeling extra weighed down - you’re essentially wearing over half the weight of your skin on top of the weight of your skin.

But alas, that’s just one of the reasons why the call the skin the largest organ the human body has to offer. It’s heavy and covers our entire body, head to toe.