”I am Your Body”

HAIR

     FOR ALL PRACTICAL purposes I am useless - one of the few parts of your body with nothing to do. Yet you are more concerned about me than about most of your life-and-death organs. You and your opposite gender partner, lavish time, attention and money on me and my associates. I am hair No. 56,789 in your head and will speak for the millions of others scattered over your body.

We hairs come in various sizes and shapes: stiff and short in the eyebrows; long and soft on the head; downy and virtually invisible on most other body areas. There are l00,000 of us on your scalp, 30,000 in a beard. We are among the fastest growing tissues in your body. Each year we will produce about 5 1/2 inches of beard and about 5 inches of scalp hair.

We hairs served primitive man well: brows protected eyes, facial hair gave warmth in winter, pubic and armpit hair lessened chafing. But for the most part these jobs lost importance. Indeed, shaving the beard became a military necessity - the whiskers made too convenient a handle for a foe to hang on to while he went to work with a sword.

What are we hairs and where do we come from? Buried about an eighth of an inch down in the corium - the layer of skin beneath the epidermis that contains the blood and nerves - I have a tiny follicle. The follicle is simply a minute hair factory, an amazing and complex affair that operates 24 hours a day for up to seven years and then shuts down for rest and repairs. After a rest period, my follicle will crank up and start producing again. I usually drop out and am replaced by a new hair - You lose some 75 of us scalp hairs a day.

At two months our follicles started forming when you where in your mother's womb. They began producing a silky down called lanugo. At seven months you shed this.

When you where a child, soft, short "vellus" hair covered most of your body. At puberty, many of the follicles that had been producing vellus hair changed and started producing the coarser "terminal" hair that you have today. Another curious point about hair - eventually many scalp follicles may degenerate and start producing vellus hair instead of terminal hair or they may shut down completely. That's ordinary baldness. A high percentage of men are bald or balding by midlife, but relatively few women.

When you reach old age, we hairs will become smaller in diameter as your factory decreases in size. Our quality, as a general rule, will become poor.

When you pluck one of your scalp hairs, you may note a small club at the end. You're afraid the hair won't be replaced. It will. This club is simply the terminal end of a hair from a resting follicle, which is about to be shed anyway.

The essential production of hair follicles is protein. We hairs are made up almost entirely of protein. It's amazing that anything as tiny as a follicle could turn out a product so intricate. My outer layer has overlapping cells that look like shingles on a roof. This layer gives strength and protection. My middle layer contains fatter elongated cells that give bulk. I am quite elastic and under certain conditions can be stretched in length. I am also surprisingly strong and can support about a three-ounce weight.

As my follicle creates and arranges my cells to make this complex structure, it gives me a little squirt of coloring matter, which is parceled out in tiny granules. Hair color depends on the shape, number and distribution of these granules, as well as on the type of pigment present - brown-black or yellow-red. Each follicle also has attached sebaceous glands to provide its hair with lubricating and waterproofing fat.

Newly produced hair cells are living affairs. As they are pushed upward through the hair canal, a hardening process called keratinization sets in. The part of my hair above the surface is dead. The keratin we hairs are made of is also found in the horns of a cow, feathers of a duck and hoofs of a goat.

The production rate of individual follicles varies around your body. Some - like those of your eyebrows and eyelids - rest most of the time. But plucking eyebrows stimulates follicle activity, and results in more speedy re-growth than if they are shaved. My follicle is one of the more active ones. It produces about half an inch of hair a month. The follicles that produce whiskers are slightly faster. Although women have about the same number of follicles as men, most of her follicles produce a quite different type of hair. Her body and facial hair is mostly a fine, almost invisible down - the same vellus hair that covered you as a child. She can thank her stars that this is so. Otherwise she might be bearded and hairy-chested.

Our follicles produce hair that is straight, wavy or curly. In cross section we might have one of three basic shapes: round, oval or flattened. Round is for straight hair; oval is for wavy hair; flattened is for kinky hair. Of course, there are degrees in between. The flatter we hairs are, the curlier we are, the rounder we are, the straighter.

When you are around 45 you will notice gray hairs. This is because my pigment glands are slowing production. In time they will shut down entirely. Then you will have white hair.

In a sense, we hairs are record keepers for your body. Minute portions of what you consume are apt to show up in us, particularly metals. You fret about lead pollution in today's air from motor exhaust. If you had a snippet of your grandfather's hair, it might contain several times as much lead as yours. The old gentleman could have got it from lead plumbing and lead-glazed earthenware. Should someone decide to slip arsenic into your tea, a good chemist could examine your hair and know, to within 48 hours, when you were dosed.

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