I am a huge fan of Bill Bryson. I just finished reading “The Body: A Guide for Occupants”. The book illustrates how miraculous, wondrous, special and mysterious our bodies are. We are not cheap. The full cost of building a new human being, using the obliging Benedict Cumberbatch as a template, would be £96,546.79. Where carbon, calcium, phosphorus and potassium would be the biggest outlays. That excludes VAT.
How our body works is amazing
Most of the best technology on Earth is right here inside us. And everybody takes it almost completely for granted. For example:
- You blink fourteen thousand times a day – so many that your eyes are shut for twenty-three minutes of every waking day.
- Every second of every day, your body undertakes a literally unquantifiable number of tasks(a vigintillion) without requiring an instant of your attention.
- We make between 4,100 to 10,000 facial expressions per day.
- Your ear is filled with 2,700 delicate hair-like filaments called stereocilia, which wave like ocean grasses as sound waves pass across them.
- The nerve cells in your nose contain some 350 to 400 types of odour receptors. Receptors are stimulated not by the shape of molecules but by how they vibrate.
- We can detect at least a trillion and possibly even more odours.
- We have about ten thousand taste buds. Most on the tongue, but also on the throat and in the gut.
- Your heart beats about 100,000 times a day, as many as 3.5 billion times in a lifetime; it rhythmically pulses to push blood through your body.
- The liver takes part in some 500 metabolic processes. Essentially it is the body’s laboratory.
- The kidneys process about 180 litres of water and 1.5kg of salt.
- The hands and feet together have more than half the bones in the body.
- It takes one hundred muscles just to get us to stand up.
- The amount of electricity within your cells is a thousand times greater than that within your house.
- Every time you breathe, you exhale some 25 sextillion (that’s 2.5 × 1022) molecules of oxygen.
- You take a breath 550 million times or so over a lifetime.
- Pain signals travel at 20 metres a second, nearly 270 miles an hour.
- It takes seven billion billion billion (that’s 7,000,000,000,000,000,000,000,000,000, or seven octillion) atoms to make you.
- Your lungs smoothed out, would cover a tennis court, and the airways within them would stretch from London to Moscow.
- The length of all your blood vessels would take you two and a half times around the Earth.
- If you formed all the DNA in your body into a single fine strand, it would stretch ten billion miles beyond Pluto.
- You would need twenty billion DNA strands laid side by side to make the width of the finest human hair.
- Every cell in your body (strictly speaking, every cell with a nucleus) holds two copies of your DNA.
- Nobody knows how many types of protein there are within us, but estimates range from a few hundred thousand to a million or more.
- Our bodies are a universe of 37.2 trillion cells.
- You shed skin copiously, some twenty-five thousand flakes a minute, over a million pieces every hour.
- Pacinian corpuscle can detect a movement as slight as 0.00001 millimetres.
- You have about 100,000 microbes per square centimetre of your skin.
- You will likely have some forty thousand species of microbe calling you home – nine hundred in your nostrils, eight hundred more on your inside cheeks, 1,300 on your gums, and as many as 36,000 in your gastrointestinal tract.
- Each of us contains about thirty trillion human cells and between thirty and fifty trillion bacterial cells.
- You also have a personal repertoire of microbes consisting of fungi, viruses, protists (amoebas, algae, protozoa and so on), and archaea.
In other words, you are not a person but a world – a vast and jouncing wealth of marvellously rich ecosystems.
The book takes a journey through the different aspects of the human body, starting with the brain. Followed by the eyes, the ears, the nose, the mouth, the throat, speech, taste, the heart, blood, chemistry, skeleton, muscle, cells, the immune system, lungs, food, vitamins, stomach, intestines, sleep, sex, nerves, pain, disease and death.
The great paradox of the brain is that everything you know about the world is provided to you by an organ that has never seen that world. The brain exists in silence and darkness, like a dungeon prisoner. It has no pain receptors, literally no feelings. To your brain, the world is just a stream of electrical pulses, like taps of Morse code. Sitting quietly, doing nothing at all, your brain churns through more information in thirty seconds. A morsel of cortex one cubic millimetre in size – about the size of a grain of sand – could hold 2,000 terabytes of information, enough to store all the movies ever made, trailers included, or about 1.2 billion copies of this book. The human brain is estimated to hold something in the order of 200 exabytes of information; it makes up just 2 per cent of our body weight but uses 20 per cent of our energy.
The eyes send a hundred billion signals to the brain every second, and only about 10 per cent of the information comes from the optic nerve when you see something. Each visual input takes a tiny but perceptible amount of time – about 200 milliseconds, or one-fifth of a second. The brain does a truly extraordinary thing: it continuously forecasts what the world will be like one-fifth of a second from now, and that is what it gives us in the present.
Programming your brain
That means that we never see the world as it is at this very instant but rather as it will be a fraction of a moment in the future. We spend our whole lives, in other words, living in a world that doesn’t quite exist yet. All the richness of life is created inside your head. What you see is not what is, but what your brain tells you it is, and that’s not the same thing at all. That’s quite remarkable that a significant part of everything you ‘see’ is actually imagined. Hence the amazing prospect of programming your brain:
The book also lists some bizarre syndromes (to illustrate how strange the brain is). Anton-Babinski syndrome, for instance, is a condition in which people are blind but refuse to believe it. In Riddoch syndrome, victims cannot see objects unless they are in motion. Capgras syndrome is a condition in which sufferers become convinced that those they know well are imposters. In Klüver-Bucy syndrome, the victim develops urges to eat and fornicate indiscriminately (to the understandable dismay of loved ones). Perhaps the most bizarre of all is Cotard delusion, in which the sufferer believes he is dead and cannot be convinced otherwise.
If an orange-flavoured drink is coloured red, you cannot help but taste it as cherry. The fact is that odours and flavours are created entirely inside our heads. That is why they invented gastrophysics. It is amazing how your taste can be manipulated. https://www.ronimmink.com/what-ceo-entrepreneurs-and-marketers-can-learn-from-gastrophysics/
Cartilage is remarkable. It is many times smoother than glass: it has a friction coefficient five times less than ice. Imagine playing ice hockey on a surface so smooth that the skaters went sixteen times as fast.
Bone is stronger than reinforced concrete yet light enough to allow us to sprint. All your bones together will weigh no more than about 20 pounds (nine kilograms), yet most can withstand up to a ton of compression.
Activity and rest
Our ancient ancestors worked hard for what they ate. Consequently, they ended up with bodies designed to do two somewhat contradictory things: to be active much of the time but never to be more active than absolutely necessary. You have to understand that we evolved to be hunter-gatherers. We used to expend a lot of energy to acquire food, but not wasting energy when you don’t need to.’ So exercise is important, but rest is vital. Since our ancestors had to survive lean times as well as good, they evolved a tendency to store fat as a fuel reserve – a survival reflex that is now, all too often, killing us. In that half-century or so, the average woman’s weight has gone from 63.5kg (10 stone) to 75.3kg (11 stone 12 pounds). The men have gone from 73.5kg to 89kg (a gain of more than 2 stone).
Allergies have become a bane of modern life. Roughly 50 per cent of people claim to be allergic to at least one thing, and many claim to be allergic to many things. The richer the country, the more allergies its citizens get. No one knows why being rich should be so bad for you.
An estimated 300 million people worldwide have asthma today; in Hong Kong, asthma rates are 15 per cent, while in heavily polluted Guangzhou, they are just 3 per cent, exactly the opposite of what one would expect. No one can account for any of this. Indeed, where asthma is concerned, no one knows much of anything. Asthma is that it is primarily a Western disease. There is something about having a Western lifestyle that sets up the immune system in a way that makes it more susceptible.
Many of our fruits and vegetables are nutritionally less good for us than they were even in the fairly recent past. Modern fruits, for instance, are almost 50 per cent poorer in iron than they were in the early 1950s and about 12 per cent down in calcium and 15 per cent in vitamin A. Modern agricultural practices, it turns out, focus on high yields and rapid growth at the expense of quality. The United States is in the bizarre and paradoxical situation that its citizens are essentially the world’s most overfed people but also among the most nutritionally deficient ones.
Adults in the West produce about 200g of faeces a day – a little under half a pound, about 180 pounds a year, 14,000 pounds in a lifetime. Every gram of faeces you produce contains 40 billion bacteria and 100 million archaea.
We have body clocks not just in the brain but all over – in our pancreas, liver, heart, kidneys, fatty tissue, muscle, virtually everywhere – and these operate to their own timetables, dictating when hormones are released, or organs are busiest or most relaxed. Fifty-six of the hundred bestselling drugs in use today target parts of the body that are time-sensitive. Take them at the wrong time, and they may well be less effective or possibly not effective at all.
Until recently, drug trials very often excluded women, primarily because it was feared their menstrual cycles could skew results. In 2007, the journal Pain reviewed all of its published findings over the previous decade and found that almost 80 per cent had come from male-only tests.
Several studies have reported serious falls in sperm counts in recent decades. The sperm counts in Western nations fell by more than 50 per cent between 1973 and 2011.2 The number of spermatozoa produced by the average man in the prime of life varies from one million to 120 million per millilitre, with an average of about 25 million per millilitre. This means that a typical sex act produces enough sperm to repopulate a medium-sized country at the very least.
There is no pain centre in the brain, no one place where pain signals congregate. Perhaps the weirdest irony is that the brain has no pain receptors, yet it is where all pain is felt. All pain is private and intensely personal. We still don’t know exactly how the brain constructs the experience of pain. Pain is curiously mutable. It can be increased, attenuated or even ignored by the brain, depending on the situation. In many ways, we feel the pain we expect to feel.
More than eighty thousand chemicals are produced commercially in the world today, and, by one calculation, 86 per cent of them have never been tested for their effects on humans. Pollutants in air and water contribute to cancers; it has been estimated that it may be as much as 20 per cent.
America differs from other countries in the colossal costs of its health care. A survey by the New York Times found that an angiogram costs an average of $914 in the United States and $35 in Canada. $765 billion a year – a quarter of all health care spending – is wasted on pointless precautionary manoeuvres. In 2013, an international team of researchers investigated common medical practices and found 146 in which a current standard practice either had no benefit at all or was inferior to the practice it replaced.
We have reached the decidedly bizarre point in health care in which pharmaceutical companies produce drugs that do exactly what they are designed to do but without necessarily doing any good. A study in 2004 involving 24,000 patients found that atenolol did indeed reduce blood pressure but did not reduce heart attacks or fatalities compared with giving no treatment at all. People on atenolol expired at the same rate as everyone else, but, as one observer put it, ‘they just had better blood-pressure numbers when they died.
As a tuberculosis researcher observed years ago, ‘Mice don’t cough.’ Another problem with clinical trials is that test subjects are nearly always excluded if they have any other medical conditions or are on other medications since those considerations could complicate results. We rarely know, for instance, what happens when various medications are taken in combination.
By one calculation, if we found a cure for all cancers tomorrow, it would add just 3.2 years to overall life expectancy. Eliminating every last form of heart disease would add only 5.5 years. That’s because people who die of these things tend to be old already; for every year of added life that has been achieved since 1990, only 10 months is healthy. I think we have to accept that slowing down, losing vigour and resiliency, experiencing a steady, ineluctable diminution in the ability to self-repair – in a word, ageing – is universal across all species, and it is intrinsic: that is, it is initiated from within the organism. It happens to us all. Every day, around the world, 160,000 people die. That’s about 60 million fresh bodies a year, roughly equivalent to killing off the populations of Sweden, Norway, Belgium, Austria and Australia combined year after year.
Live for 1000 years
However, Dr Aubrey de Grey, chief science officer of the SENS Research Foundation of Mountain View, California, believes that some people alive right now will live to be one thousand.