The skin is made up of two main layers, the dermis, an inner, living layer, and the epidermis, an outer layer of dead cells. The epidermis is several cells thick and is composed of a stratified squamus epithelium of keratinized cells. An epithelium is a layer of cells that serves as a protective covering over some surface. Squamus means that they are flattened. Stratified means that it is layered.
Keratin is a fibrous protein that makes the cells stiff and horny.
Your hair and fingernails are made up of keratin. The epidermal layer of your skin is totally replaced every 52 to 75 days. The dermis is made up of collagen and elastic fibers, permeated by hair follicles, nerves, blood vessels, nerves, fat globules, and sweat glands. The skin is also a huge sensory receptor for heat, cold, pain, touch, and tickle. This material may not be reproduced in any form without express written permission.