The human body is often compared to a powerful machine.
But it's so much more than that. It works for decades 24 hours a day without (for the most part) regular maintenance or the installation of spare parts.
It works on water and a few organic compounds, is soft and fairly beautiful, reproduces itself with enthusiasm, makes jokes, feels affection and appreciates a red sunset.
How many machines do you know are all possible? There is no doubt about it. You really are a miracle.
And how do we celebrate the glory of our existence? Well, for most of us by exercising and eating as much as possible.
Think of all the mess you throw in your throat and how much of your life you spend in an almost vegetative state for a glowing screen.
But in a friendly and wonderful way, our bodies take care of us, extract nutrients from the various foods that we push into our faces, and somehow hold us together.
The human body works for decades 24 hours a day without (for the most part) regular maintenance or the installation of spare parts. Depicted is Bill Bryson
Even if you do almost everything wrong, your body will maintain and maintain you. Most of us testify to this in one way or another.
Five out of six smokers do not get lung cancer. Most people who are main candidates for heart attacks do not get a heart attack.
It is estimated that between one and five of your cells become cancerous every day and your immune system catches and kills. Think about that.
A few dozen times a week, more than 1000 times a year, you get the most dreaded disease of our age, and every time your body saves you.
Our bodies are a universe of 37.2 trillion cells that more or less always work in a perfect concert.
It is estimated that between one and five of your cells become cancerous every day and your immune system catches and kills. Think about that
A pain, a hint of indigestion, the strange bruise or pimple is about everything that announces our imperfection in the normal course of events.
There are thousands of things that can kill us – a little more than 8,000 according to the World Health Organization – and we escape each of them except one. For most of us, that's not a bad deal.
"Feel this," the doctor tells me. We are in the dissecting room of the University of Nottingham Medical School and Dr. Ben Ollivere focuses my attention on a piece of loose snakes in the upper chest of a male body.
I am struck by a powerful thought. In the dissecting room, the human body is no longer a wonderful piece of precision technology. It is meat.
Ben instructs me to put and feel my gloved finger in the inside of the tube. It is stiff like uncooked pasta.
I have no idea what it is. & # 39; The aorta, & # 39; says Ben, with what seems proud.
I am frankly surprised. "So that's the heart?" I say, pointing at the formless clog next to it.
A few dozen times a week, more than 1000 times a year, you get the most dreaded disease of our age, and every time your body saves you. Our bodies are a universe of 37.2 trillion cells that more or less always work in a perfect concert
Ben nods. "And the liver, pancreas, kidneys, spleen," he says, pointing to the other organs of the abdomen.
Ben is an old friend and a leading academic and trauma surgeon. There is nothing in the human body that doesn't fascinate him.
"Just think of everything that the hand and wrist do," he says. He gently pulls an exposed tendon in the forearm of the cadaver at the elbow and, to my surprise, the little finger moves. Ben laughs at my shock and explains that we have grabbed so much in a small space that much of the work has to be done remotely, such as strings on a puppet.
"The wrist is just something beautiful," he continues. "Everything must go through it – muscles, nerves, blood vessels, everything – and yet it must be fully mobile at the same time.
"Think of all the things you need to do – take a lid off a jam jar, say goodbye, turn a key in a lock, replace a light bulb. It is a beautiful piece of technology. & # 39;
Ben & # 39; s field is orthopedics, so he likes bones and tendons and cartilage like other people like expensive cars or excellent wines. & # 39; Do you see that? & # 39; He says, tapping a small, smooth, very white obtrusion at the base of the thumb, which I consider a little exposed bone.
"No, it's cartilage," he corrects. "Cartilage is also remarkable. It is many times smoother than glass: it has a coefficient of friction five times less than ice.
& # 39; Imagine playing ice hockey on a surface that is so slippery that the skaters went 16 times faster. That is cartilage.
& # 39; But unlike ice, it is not brittle. It doesn't crack under pressure like ice would. And you grow it yourself. It is a living creature.
There are thousands of things that can kill us – a little more than 8,000 according to the World Health Organization – and we escape each of them except one. For most of us, that's not a bad deal
"Nothing is matched in engineering or science. Most of the best technology that exists on Earth is here in us. & # 39;
Before we continue, Ben examines the pulse. "You should never try to kill yourself by cutting your wrists," he says.
"All those things that come in are wrapped in a protective band called a fascial sheath, making it very difficult to go to the arteries.
"Most people who cut their wrists fail to kill themselves, which is undoubtedly a good thing."
He is briefly attentive. "We are designed not to die." This seems a somewhat ironic thing to say in a large room full of dead bodies, but I take his point.
We tend to regard our bones as inert scaffolding, but they are also living tissue. They grow bigger with exercise and use just like muscles.
"The bone in the serving arm of a professional tennis player can be 30 percent thicker than in his other arm," said Margy Pratten, an associate professor of anatomy, whom Rafael Nadal cited as an example.
Look at the bone through a microscope and you will see a complex series of productive cells, just like in any other living creature. "Bone is stronger than reinforced concrete," says Ben, "but still light enough to make us sprint." All your bones together weigh no more than about 20 lb (nine kilograms), but most can withstand a ton of compression.
& # 39; Bone is also the only tissue in the body that has no scars, & # 39; Ben adds. & # 39; If you break your leg, you cannot see where the break was after healing. There is no practical benefit for that. Bot just seems to want to be perfect. & # 39;
Even more remarkable is that the bone grows back and fills a void.
"You can get up to 30 centimeters of bone from one leg, and with an external frame and some sort of stretcher you can grow it back," says Ben. "Nothing else in the body will do that." In short, bone is amazingly dynamic.
The skeleton is of course only a part of the vital infrastructure that keeps you upright and mobile. The bulk of you, no matter how modest you are, is muscle.
You have more than 600 muscles in total. We tend to notice our muscles only when they hurt, but of course they are constantly at our service in 1000 unappreciated ways – puckering our lips, blinking our eyelids, moving food through the digestive tract.
You need a dozen to move your eyes over the words that you are reading now. The simplest movement of the hand – say a vibration of the thumb – can include ten muscles. We don't even consider many of our muscles as muscles – for example, our tongue and heart.
All in all you are around 40 percent muscle if you are a reasonably slim man, slightly less if you are a comparatively similar woman, and if you just keep that muscle mass, you consume 40 percent of your energy surcharge when you are at rest and much more when you are active. Because muscles are so expensive to maintain, we sacrifice muscle tone very quickly if we don't use it.
Studies by NASA have shown that astronauts – even on short missions, from five to 11 days – lose up to 20 percent muscle mass.
All these things work together in an agile and beautiful choreography. Nowhere is this better demonstrated than in your hands.
Within each of them you have 29 bones, 17 muscles (plus 18 more in the forearm but hand control), two main arteries, three main nerves (one of which is the ulnar nerve, which you feel in your elbow when you & 39; funny bone & # 39; touches) plus 45 other named nerves and 123 named ligaments, all of which must coordinate their action with precision and delicacy. The hand is undoubtedly a beautiful creation, but not all parts are equal.
Within each of them you have 29 bones, 17 muscles (plus 18 more in the forearm but hand control), two main arteries, three main nerves (one of which is the ulnar nerve, which you feel in your elbow when you & 39; funny bone & # 39; touches) plus 45 other named nerves and 123 named ligaments, all of which must coordinate their action with precision and delicacy
If you curl your fingers in a fist and try to straighten them one by one, you will notice that the first two pop up obediently enough, but the ring finger does not seem to want to straighten at all. The position on the hand means that it cannot really contribute to fine movements and is therefore less discriminatory.
Surprisingly, we don't all have the same components in our hands. About 14 percent of us miss a muscle called the palmaris longus, which helps keep the palm tense.
Top athletes and women who rarely need a strong grip to perform are rarely missing, but otherwise they are pretty unnecessary.
It is often noted that we have opposite thumbs (meaning that they can touch the other fingers, giving them a good grip) as if this is a unique human trait.
In fact, most primates have opposite thumbs. Ours are simply smoother and more mobile.
What we have in our thumbs are three small but beautifully named muscles that are not found in any other animals, including chimpanzees: the extensor pollicis brevis, the flexor pollicis longus and the first volar interosseous from Henle.
By working together, these thumb muscles enable us to grasp and manipulate tools with certainty and delicacy. You may never have heard of it, but these three small muscles form the heart of human civilization. Take them away and our greatest collective achievement can be that ants with chopsticks wink at their nests.
The feet, our other disproportionate outposts, receive much less praise and attention when it comes to discussing the functions that make us special, but in fact the feet are also pretty amazing.
The foot must have three different things: shock absorber, platform and push member. With every step you take – and in the course of your life you will probably take something close to 200 million of them – you perform those three functions in that order.
Our feet are designed to grasp, so you have an abundance of bones in it. They are not designed to support a lot of weight, which is why they hurt or stand at the end of a long day of walking. Ostriches have solved this problem by fusing the bones of their feet and ankle together – but then ostriches have had 250 million years to adapt to walking upright – about 40 times as long as we have had.
The miracle of human life is not that we are endowed with a number of weaknesses, but that we are not overwhelmed by them.
As we have seen, our genes come from ancestors who were usually not even human. Some of them were fish. Many more were small and hairy and lived in burrows. You are the product of three billion years of evolutionary tweaks.
We would all be much better off if we could just start over and give ourselves bodies built for our specific human needs: walk upright without breaking our knees and backs, swallow without the increased risk of suffocation, babies & # 39; s hand out like from a vending machine.
As modern people, we pass our existence within this wondrous, warm wobble of flesh and yet we almost take it for granted. How many of us even know about where the spleen is or what it does? Or what are our lymph nodes doing?
How many times a day do you think you are blinking? Five hundred? Thousand? Of course you have no idea. Well, you blink 14,000 times a day – so much that your eyes are closed for 23 minutes every day.
But you never have to think about it, because your body performs a non-quantifiable number of tasks every second of the day – a quadrillion, a non-trillion, fifteen minutes, a vigintillion (these are real measures); at least a number that you can't imagine – without asking for a moment of attention.
In the second or so since you started this sentence, your body has created a million red blood cells. They are already running around you, flowing through your veins and keeping you alive.
Each of those red blood cells will rattle around you 150,000 times, repeatedly deliver oxygen to your cells and then, battered and useless, present themselves to other cells to be silently killed for your greater good.
A total of seven billion billion (that is, 7,000,000,000, 000,000,000,000,000,000 or seven october) atoms are needed to make you. No one can say why those seven billion billion billion have such an urgent desire to be you.
But your atoms are only building blocks and do not live themselves. It is not so easy to say where life begins exactly.
The basic unit of life is the cell – everyone agrees. The cell is full of busy things – ribosomes and proteins, DNA, RNA, mitochondria and many other microscopic arcana – but none of these are alive themselves. The cell itself is just a compartment – a kind of small space to hold them and is in itself just as non-living as any other room.
But somehow you have life when all these things are brought together. That is the part that escapes science. I hope it will always be that way.
© Bill Bryson
Short extract of The Body: A Guide For Occupants, by Bill Bryson, published by Doubleday on October 3 for £ 25.
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