Sunday, February 25, 2007

Stuff You Didn't Know About Your Skin

And You Thought You Knew About Skin

The largest by far of our body organs, skin ranks among the least understood by most people. Most of us know about UVB radiation causing skin cancer, but not so many know that that is only when an excessive amount of sunlight strikes the skin over a long period of time. At that, only after many years does the cancer appear, often as much as two decades or more.

Skin cancer mostly appears at the former sites of bad sunburns. Our skin needs sunlight—about 10 to 15 minutes of direct sunlight per day—in order that our bodies can make vitamin D, which we can't do on our own.

Vitamin D, among its many purposes, keeps us from suffering from SAD (Seasonal Affective Disorder), a condition we might call depression or the winter blahs because those of us in cold climates tend to stay inside more when the outside is cold.

SAD is a real threat for almost everyone in areas that get very cold in winter. Even in the middle of the day, when sunlight is brightest, we can't get enough ultraviolet radiation to help us make the vitamin D we require for good physical and emotional health because of the sun's low angle.

We must either supplement with OTC (over the counter) tablets of vitamin D or use a lamp that mimics the sun by giving off UV rays directly onto our skin.The amount of vitamin D supplement varies considerably from one person to another.

Not enough has been studied of the effects of low levels of vitamin D in our systems to know how many of the eccentric, obsessive or just excessive behaviours we see during winter in people who live in cold climates may be attributed directly to vitamin D deficiency.

Nor do we know for certain how the deficiency may affect our personal relationships with spouse, family, friends or workmates. However, when something seems to be wrong about the behaviour of someone close to us during the wintertime, a suggestion to consult a doctor or pharmacist about taking a vitamin D supplement might be in order.

Every time we look into a mirror we see this large body organ, our skin, but we tend to think of what we see as "me" rather than as one part of us that may require attention other than by using cosmetics. For example, dry skin indicates insufficient water is reaching skin cells. Drinking more water is a more efficient and cheaper method of rehydrating skin than covering it repeatedly with topical lotions.

Here are several more facts about skin that few people know.

The skin of an average adult weighs in at nine pounds and contains more than 11 miles of blood vessels. Its mass alone makes it worth taking seriously.

In hot weather, the skin releases as much as three gallons (over 10 litres) of water each day in the form of sweat. (Okay, perspiration, for those more sensitive readers, but it still comes from sweat glands.) As water is the major component of every part of the body, not replacing lost water sufficiently will impact health.

Body odour begins with the release of a different kind of sweat, a fatty liquid secreted by the apocrine glands which are found mostly around the armpits, genitals and anus. Bacteria on the skin eat the fatty stuff and leave behind a smell that is considered unpleasant in western cultures(but not in all cultures).

Human breasts mostly consist of fat, as they are a modified form of the apocrine gland. Yes, they are mostly bags of fat.

Some people are born without skin ridges we call fingerprints. They have rare genetic defects known as Naegali syndrome or dermatopathia pigmentosa reticularis.

Our atmosphere at any given moment contains about one billion tons of dead skin and other organic matter (such as hair). The skin of each person shucks off about 50,000 cells every minute. House dust mostly consists of dead skin cells.

The skin contains about five different kinds of receptors that account for our sense of touch. Which are the most sensitive parts of the human body?

The lips (the most sensitive), fingertips, palms, lips, tongue, nipples, penis and clitoris have a kind of receptor known as Meissner corpuscles. They respond to pressure as light as the weight of a fly--that's the insect variety--about 20 milligrams.

Do blind people really develop greater sensitivity to touch and hearing? The visual cortex of blind people rewires itself in the brain to respond to sounds and touch stimuli. Blind people "see" (process information coming into the brain) the world through touch and sound.

The term "in the buff" to refer to being naked began in the 17th century in England where soldiers wore leather tunics known as buffs. Their light brown colour supposedly looked to some like the colour of English buttocks.

White skin developed between 20,000 and 50,000 years ago when darker-skinned peoples moved to colder climates in Europe and Asia. The lighter skin colour (less of the colouring agent melanin) allowed northerners to absorb more of the sun's then-precious ultraviolet, making them healthier.

Finally, a 16th century anatomy book by Andreas Vesalius, called DeHumani Corporis Fabrica (On the Fabric of the Human Body), had a cover topped with human skin. Harvard Law School, Brown University and the Cleveland Public Library all have books with covers topped with human skin stripped from executed prisoners or the poor.

Don't even ask about reprints.

(Primary data source: Discover magazine, February, 2007)

Bill Allin
Turning It Around: Causes and Cures for Today's Epidemic Social Problems, a book about real and inexpensive solutions to communityproblems most people think are inevitable evils of modern society. Theyaren't. We just have to look in the right place.
Learn more at
Contact author Bill Allin at

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