We all have one, but most of us probably take it just a little bit too much for granted – the human body. The closer you study human physiology the more amazing it is, as the 20 facts that follow illustrate. After you’ve read them, you might well consider spending a bit more time contemplating how miraculous the complexities and capabilities of the human anatomy are.
20. Stomach acid that can dissolve razor blades
For obvious reasons, scientists have not been able to prove that a razor blade will dissolve in stomach acid by getting a volunteer to swallow one. But what the clever researchers did back in 1997 was to create a fake stomach – basically a glass jar containing artificial stomach acid. The resulting paper, In Vitro Effects of Simulated Gastric Juice on Swallowed Metal Objects concluded, “Corrosion of razor blades occurs rapidly in the normal stomach.” So there you have it. But please don’t try this at home.
19. Renewing your skin
To rejuvenate your skin, there’s absolutely no need to pay top dollar for fancy cosmetic treatments. In fact, you need do absolutely nothing to get hold of a completely regenerated pelt. Without any conscious action or thought from you, your skin, the body’s largest organ, obligingly renews itself completely every 27 days on average. And here’s an extra fun fact for free – the average person’s skin weighs about six pounds.
18. (Nearly) indestructible bones
Although sticks and stones may break your bones, it requires a lot of force to achieve those fractures. Bones are actually incredibly strong. Weight for weight, your bones have more strength than steel, and they’re four times as robust as concrete. In fact, a single cubic inch of bone can withstand a weight of 19,000 pounds. That’s about the weight of one African bull elephant and a decent-sized SUV. Although you seldom see an elephant driving one of those.
17. Hair that goes on and on and on and…
Rapunzel of fairy-tale fame had prodigiously long hair. But actually, any human can compete with her, assuming they’ve not fallen prey to baldness. On average, each human hair grows about two-fifths of an inch per month. Since the average person boasts 150,000 separate hairs, that’s an aggregated total growth of 10 miles each and every year. Okay, it’s a slight cheat since each individual hair only grows a bit more than four-and-a-half inches per year, but it’s still undeniably impressive.
16. Climbable human hair?
And while we’re on the topic of Rapunzel, you’ll recall that in the tale her princely lover climbed up her hair, anxious to gain entry to her high tower. Could that be possible? Well, the hair would certainly be strong enough. A whole head of human hair is robust enough to lift more than 26,000 pounds, so would support the weight of an average prince easily. Unfortunately, his weight would also haul Rapunzel right out of the tower. So the truth is, in real life, the prince actually needs a ladder.
15.The insignificant pinkie
Actually, not quite so insignificant. If you thought the only purpose of the pinkie was as a digit for the British upper classes to stick out at a weird angle while they drink tea, think again. It turns out that if by some terrible mishap you lost your pinkie, you’d also lose an astonishing 50 percent of the strength of your entire hand. The power of the pinkie, apparently, comes from its union with the ring finger. Working together, the two give the hand its strength.
14. Lengthy blood vessels
Blood vessels it turns out are very long, very long indeed. If you extracted the blood vessels from a child, something you really ought not to do, they would stretch for a staggering 60,000 miles. If you did the same to an adult – again, something to be avoided – the stretched length would be nearly 100,000 miles. Long as they are, the narrowest blood vessels are incredibly fine with the thinnest measuring as little as five-thousandth of an inch in diameter, as compared to the average human hair, which is a bit more than one-thousandth of an inch.
13. One trillion connections
Modern computers have impressive data processing and memory capacities measured in the billions of bytes. But the human brain has the capacity to far outperform any computer. The brain contains one billion neurons and each one can form up to 1,000 links with other neurons. Neurons work together so that each can process multiple memories, and that means your brain is capable of one trillion connections.
12. Brain the size of a planet
The operational ability of your brain means that an average brain has a memory capacity of about one million gigabytes, the equivalent of storing three million hours of recorded TV programs. Another way to think of that amount of capacity is that you could record TV for a period of 300 years before you used up all of the brain’s memory capacity. Thankfully, the upshot of this enormous memory capacity is that you’ll never run out of space for new memories.
11. The human cell
In basic biology class we learn that all living things are made up of microscopic cells. Human beings are no different in that respect, and our bodies are composed of a huge number of individual cells. There are something like 200 different varieties of cell in our bodies – the ones pictured here are red blood cells. But just how many cells does the average body include? The staggering answer is 37.2 trillion.
10. In the blink of an eye
Most of the time, we’re not conscious of our eyes blinking – you really have to think about it to notice it happening. But blink we do, and this reflex action occurs at a surprising rate. On average, you blink between 15 and 20 times a minute. Do the math, and you’ll see that means you blink up to 19,200 times per day, assuming you’re asleep for eight hours. Research from 2012 theorized that we may blink so often to give our brains brief moments of rest.
9. A rose by any other name would smell as sweet
The title of this section paraphrases lines from Shakespeare’s Romeo and Juliet and is generally taken to mean that the name of something does not define what it really is. But what Shakespeare would certainly not have known is how many smells our noses can actually detect. According to research by scientists at Rockefeller University, the average human nose can differentiate something like an astonishing one trillion different smells.
8. In a heartbeat
We depend on our heart beating to keep us alive as it pumps blood around our bodies. But most of us probably don’t appreciate just how hard our hearts work. The average heart beats some 101,000 times each day. That’s almost 37 million times for each year of your life. And the heart’s pumping action sends about 590 pints of blood around your body in just one hour, almost 5.7 million pints each year.
7. Long-distance blood
Having recognized the extraordinary strength of the heart as it pumps your blood around your body, it’s also worth thinking about the blood itself. Nearly 12 pints of blood travels around your body every single minute of your life. And that means your blood makes a journey of some 12,000 miles every day. Flying that number of miles will comfortably get you from Los Angeles to Moscow and back.
6. DNA: longer than you think
We know that our DNA, or deoxyribonucleic acid to give it its full name, is pretty important since it carries the genetic code that defines us. Swiss doctor Friedrich Miescher first discovered DNA in 1869, although he didn’t realize what he’d stumbled across secreted in discarded bandages. Our understanding of DNA has advanced in leaps and bounds since then. But there’s a lot to study. If you took each coil of DNA in your body and unraveled it, it would extend for 10 billion miles.
5. What’s in your mouth?
“Don’t speak with your mouth full” is an admonishment that many of us heard from our parents when we were children. But it actually turns out that your mouth is always full, whether you have food in it or not. What your mouth is full of are bacteria, billions of them. They just love the mouth’s saliva moistened atmosphere with its temperature of 95 °F. Professor Sigmund Socransky told the Harvard Gazette that, “In one mouth, the number of bacteria can easily exceed the number of people who live on Earth.”
4. All in the hands
They’re pretty incredible things hands and with the right training just one finger can support the body’s whole weight. But in fact, the strength of the hand is not contained in the fingers and palms themselves but rather in the muscles of the forearm. The power of those muscles is transferred to the hand by tendons routed through the wrist. So your hand actually operates a bit like a puppet with tendons taking the place of strings.
3. Prolific spit
Cowboys used to spit a lot as they chewed tobacco in the days of the wild west, but the habit is hardly considered polite – or hygienic – nowadays. But we all circulate surprisingly large amounts of saliva in the course of a day, as much as one-and-a-half pints. That’s about 550 pints of saliva a year that we turn over in our mouths, a lot of spit.
2. Deep breaths
We use our lungs to take in air, and the surfaces of the lungs are adapted to be able to absorb oxygen. Your left lung is a bit smaller than your right lung, and taken together, lungs on average weigh just a little less than three pounds. So it comes as something of a surprise to learn that your lungs have about 1,500 miles of air tubes contained in their structure. Also, it’s downright astonishing to consider that if you calculate the surface area of human lungs, you’ll find that they would be about the size of a tennis court.
1. Taking in air
Of course, we have to breathe to stay alive, but you may not appreciate just how often we need to do that during the course of an average lifetime. Breaking it down into smaller time spans, on average, each person breaths about 16 times a minute. Consequently, scale that up on the assumption that you’re lucky enough to live to 80, and we’re talking about well in excess of 670 million breaths in a lifetime.