You have perhaps heard that "beauty is more than skin deep." While that is certainly true, the skin itself is beautiful and tells us a lot about people. For example, we recognize one another mostly by the skin on our face. The skin's blood supply and facial muscles even permit us to tell on sight when people are happy, sad, angry, or embarrassed. The skin is the largest organ in our body (weighing about 10 pounds [4.5 kg] in the adult) and covers the entire surface of our body, including our eyes, where the skin covering is conveniently transparent. Being on the surface, skin is the most accessible organ of our body, and thus must be marvelously resistant to our vain efforts to "improve" it with pigments, chemicals, punctures, and tattoos.
Skin, Thick and Thin
Skin is generally classified as thick skin (on our palms and soles) and thin skin (on the rest of our body). With callouses, thick skin can reach thicknesses of nearly half an inch (13 mm). Thin skin varies in thickness from about 0.5 mm on the eyelid to about 2 mm on the back (1 mm is about the thickness of a dime). Skin is made up of three major layers called the epidermis, dermis, and hypodermis. Each of these layers serves its own vitally important functions.