The Skinny on Skin
Lets water out, but not in
(HealthDayNews) -- "The most important single property of human skin is its waterproofing," says John Lenihan, the bio-engineer who wrote the book, Human Engineering, the Body Re-examined.
The skin, which is the largest organ of the human body, is actually waterproof in only one direction -- preventing water from coming in, but allowing water, mostly in the form of perspiration, to pass from inside out. Lenihan calls human skin "the original shrink-wrap." Stripped and spread out, the skin of the average male would total about 20 square feet, about 3 square feet more than the average woman.
The outer layer of skin -- onto which many of us slather all sorts of moisturizing concoctions -- is made up of dead cells, most about the thickness of tissue paper (about 1 millimeter or 0.0394 of an inch).