Читать книгу Reversing Your Hair Loss - A Practical Scientific Guide - Robert J. Hall - Страница 7

Hair does not appear overnight all of its own accord but can be seen to somehow grow outward from within the skin over time. So we really ought to start with this substrate. In other words if we want to understand what makes hair grow and how to keep it growing then we should begin with an examination of the skin itself.

Skin is the largest organ of the human body. In an adult, it covers roughly twenty square feet or so. A tall, fat man will obviously have more of it than a petite, eight-stone girl; but, by averaging it out, each human has enough of it to roughly cover one side of an ordinary house front door, including the letter box.

This skin is about one tenth of an inch thick. Again, that is just an average. The skin on the palms of the hands will be fairly thick, while the skin of the eyelids (at just one fiftieth of an inch) correspondingly thinner. Within this average one tenth of an inch are two distinct layers. These layers do not depend upon location but exist whether the skin is thick, thin or somewhere in-between. From the bottom up they are called the dermis and the epidermis. Within each of them are even thinner, but just as microscopically obvious, layers. The epidermis, for instance, comprises five such further layers.

Each square inch of this skin has, again on average, twenty capillary blood vessels, 650 sweat glands, 1,000 nerve endings and 60,000 melanocyte cells (the ones that produce the skin’s colouration and which respond to sunlight exposure). The average lump of skin hanging over the average human frame will have 2,880 such square inches.

The skin is one of our primary interfaces with the outside world. (It is not our only one, obviously; most people also have eyes and ears). This interface has evolved over millions of years to perform at least ten separately identifiable tasks.

It forms a tough, self-repairing, physical barrier against abrasion and penetrative damage from the external world.

It forms a living, chemically active barrier against the entry of pathogens (actual and potential).

It provides sensory information about the external world for our central nervous system. This information includes such basic ‘measurements’ as those of heat, pressure and vibration.

It allows for rapid and very precise internal temperature control. Those twenty capillaries per square inch are far more than is needed to simply deliver nutritive substances to the skin layers. By altering the diameter of the blood vessels, heat can be rapidly lost by radiation, convection and conduction. Constricting their diameter, on the other hand, greatly reduces their volume and, therefore, consequent heat loss. The skin also uses automatically controlled sweat glands to govern its own surface temperature through evaporative fluid loss.

It controls our internal fluid levels. It stops any significant inflow of water because it is an oil-covered barrier that is only semi-permeable in the first place. The skin also provides protection against internal fluid egress.

It has a fat storage function and can, additionally, also store a significant amount of water.

It synthesises vitamin D through the action of ultraviolet light on the cholesterol found within its layers.

It also performs excretory functions. Sweat has in it dissolved factions of blood plasma that the body wishes to remove. These include urea, salt and, in dire emergencies, even glucose.

It also, conversely, performs an absorptive role. The uppermost levels of the skin receive very little oxygen from the capillaries. As a result, oxygen from the atmosphere is allowed to diffuse through these levels allowing cellular respiration to continue within them.

It also communicates information to others. The state of our skin allows others to assess our mood, general levels of health, nutrition, infectiousness and our level of self-care, as well as racial origin and reproductive fitness.

Lest you think that your skin is exclusively yours you should know that, in fact, you share it with an astronomical number of other living things. All human skin plays host to a large collection of organisms from all five parts of the taxonomic spectrum. On it can readily be found microscopic examples of animals, plants, fungi, viruses and bacteria. Most are harmless and all are kept in check by each other. As a rough estimate, however, there are probably a thousand or so different species of bacteria alone on the average person’s skin. Unwashed skin may have greater numbers of these micro-organisms but, generally, will not have any extra types.

The precise numbers of these micro-organisms vary greatly depending upon their actual location on the skin. The average number is probably in the region of fifty million or so per square inch. In a sweating, unshaven, unwashed armpit that number could be ten times higher however. In general, though, if all the microbes that could be found on an average human were to be rolled together and placed on a plate the entire volume would probably equal that of a single baked bean, without the tomato sauce.

Any attempt to remove these micro-organisms, however, would be generally pointless, since within a few hours or so recolonisation will have occurred. Some of them could never be removed through washing in any case, because they live virtually within the skin itself.

Daily washing may be seen as part of any animal’s normal grooming patterns. It is not something peculiar to either humans or their cultures. However, the levels to which modern civilisation takes it has nothing to do with health or infection control. It is a social habit that, when looked at carefully, is actually nothing much more than a form of stress control. The fear of social exclusion because of natural body smells is the stuff of nightmares for some. Young boys seem immune to this fear, admittedly, but females and teenagers of either sex appear to be obsessive about ‘cleanliness’. This obsession is all about advertising sexual attractiveness, of course, and nothing to do with cleanliness at all.

An obvious exception to this is when surgery is about to be undertaken; under these circumstances, both the patient and the surgeon should attempt to be as clean as possible simply because pathogen transfer (cross-infection) can so easily occur. This sort of hygiene was only recognised as being useful just before the middle of the 19th century. The idea itself was British, but its earliest practical advocates were Oliver Wendell Holmes, an American doctor and Ignatz Semmelweiss, a Hungarian doctor working in Vienna.

Their recommendations were based entirely upon one easily observable fact; doctors that were made to wash their hands before seeing patients managed to kill less of them. The medical establishment simply dismissed the idea as an insult to their social rank, though, and completely opposed it. Semmelweiss, in particular, was both professionally and socially ostracised for daring to allude to the fact that obstetricians in his hospital were killing their patients because they refused to indulge in any form of hand-washing during working hours.

You might be interested to know that it was an English doctor that finally managed to change everyone’s mind and raise the pursuit of hygiene to that of a medical, ‘best working practice’ (thereby saving millions of lives). He was made a Baronet by Queen Victoria, had one of the most prestigious medical awards named after him, had two statues raised to him, had a hospital named after him, had two stamps issued in his honour, had a mountain in Antarctica named after him and even had an American mouthwash named after him. His name was Joseph Lister and you can still buy the mouthwash – it is called Listerine.

These points about cleanliness are important. As you will see later in the book, the arrogance and stupidity of the medical profession cannot be easily dismissed. When combined with the venal opportunities that modern capitalism in general and the pharmaceutical industry in particular afford, these failings border upon criminal negligence and outright fraud. It is no good relying on government agencies, either. These are not good princes that will take the robber barons to task. These agencies were bought off with corporate gold from the moment of their inception, I am sorry to report.