REBECCA ROBERTS, host:
You can live your life oblivious to the laws of physics and the basic principles of biology. Still, at some point you're probably going to ask yourself questions like, why is blood red? Why is the sky blue?
In our weekly segment Science Out of the Box, we try to answer questions like these and learn how scientists are still puzzling many of them out.
Commentator Ruth Levy Guyer is a bioethicist and the author of "Baby at Risk: The Uncertain Legacies of Medical Miracles for Babies, Families and Society." This week she reflects on the amazing properties of something very basic to our being - skin.
Ms. RUTH LEVY GUYER (Bioethicist): I told my last barefaced lie 25 years ago. The setting: the post office in Berkeley, California. The transaction: I was mailing a book to my cousin Sandy in Tennessee.
Book rate, please, I said. Is there a letter in here, the clerk asked matter-of-factly. And before I could even say yes or no, or move my head one way or the other, she said, you'll have to mail this first class. How did she know I had tucked just the most minimal note between the pages of the book? Easy. My bare face, normally somewhere between cotton candy and tickle-me-pink on the Crayola spectrum, had shifted to razzmatazz, a hue not unlike of that of Dorothy's ruby slippers.
How ironic that skin is called a protective layer, yet mine completely exposed me. And how about this misnomer? The so-called sympathetic nerves were what did me in, detecting my lie, triggering the dilation of every single capillary in my face and filling them with blush-spawning blood.
Skin is such an enigma. Why its classified as an organ I'll never understand. And it's not just any organ, but the biggest one. We each lug around 10 to 40 pounds of skin, and oddly, though we slough off the outer layer of skin each month, our looks don't change.
For some people, skin is simply a sack encasing all of the standard organs, acting as a barrier and a bridge to the outside world. But for others, skin can be defining because of its color, its sensitivity. Or its tattoos.
I read about a TV newscaster whose skin was ruining her career. Her affliction was pathological blushing, acceptable perhaps for a radio personality but not a TV anchor. She took beta-blockers, antidepressants, tried psychotherapy. Then, in desperation, she flew to Sweden, where surgeons severed key sympathetic nerves that run up to her face. She hasn't blushed since.
Had she been a different kind of mammal, say a chimpanzee, her agitation, her emotional upset, would not have been expressed through her skin, but through her hair. It's called piloerection. The chimp's hair bristles. It literally stands on end.
Evolutionary theorists suggest that proto-humans traded a body covered in hair for one that could sweat when they stepped out of the forest and into scorching sunlight to forage for food and raw materials.
Their blood, flowing near the surface of their hairless skin, cooled off, and when it then ran deeper into their hearts and livers and outsized brains, it nourished rather than fried those temperature-sensitive organs.
So we're here today with hairless skin thanks to the literal sweat of our ancestors. Emotionally, some of us are thick-skinned. Others are thin-skinned. Some get touchy and a few go postal when overwrought or blush.
Naked, expressive skin is the visible trademark we bear for being humans.
(Soundbite of song, "You've Gotta Have Skin")
Mr. JOHN LITHGOW (Performer): You've gotta have skin. All you really need is skin. Skin's the thing that if you've got it outside, it helps keep your insides in. It covers your nose. And it's wrapped around your toes. And inside, if you put lemon meringue(ph) and outside you hang your clothes. Skin has a way of feeling balmy, and without it furthermore, both your liver and abdomen would be falling on the floor and you'd be dressed in your intestine. A Siamese twin needs an extra set of skin. When the doctor knows that you're feeling sick, where does he stick his needle in? In the end of your skin.
ROBERTS: And that was John Lithgow from his CD "Singing in the Tub" with a wink and a nod to the musical "Damn Yankees."
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