Each square inch of skin contains several hundred sweat glands, blood vessels, nerve endings and oil glands. The sweat glands number more than 2 million overall.
Skin is thickest about 1/5 inch on the soles of the feet and the palms of the hands. It is thinnest on the scalp.
Fingernails grow about one millimeter (0.04 inch) every 10 to 15 days. It takes them about six months to grow from the nail bed to the tip of the finger. Nails grow faster on your favored hand and on your longer fingers.
Millions of dead skin cells are replaced each day with new ones. A cell's life lasts about 10 to 30 hours total.