The skin is composed of two layers. The upper layer is the epidermis. This layer is made of dead, flattened cells, which are continually wearing off as we move around.
The bottom of the epidermis is made of live cells that die and replace those that wear off on the surface.
Beneath the epidermis is the dermis. This layer of skin is made entirely of living cells. There are many small blood vessels and nerve endings in the dermis. Small coiled tubes in this layer open into the epidermis. These tubes are sweat glands and their openings are called pores. Hairs grow out of the skin and have their roots in the dermis. The openings from which hairs grow are called hair follicles.
The skin varies in thickness. It is very thin over the eyelids and quite thick on the palms of the hands and the soles of the feet.
