Some hair follicles have receptors for dihydroepitestosterone, a male hormone. When the hormone binds to these receptors, the follicle ceases to produce the hair shaft. A balding scalp has the potential for hair growth, but only if such receptors could be blocked. The epidermis is the more superficial, avascular, layer of the skin. It is composed of several stratified layers of thin cells, called epithelial cells, as well as melanocytes and Langerhans cells.
Races differ as to the density of melanocytes in their skin.
The outermost layer of epidermal cells is the stratum corneum. This layer consists of dead cells containing large amounts of keratin protein. These cells also release lipids into the extracellular space. The stratum corneum helps waterproof the skin and also serves as a physical barrier to microbes. Calluses and corns are areas of skin with a very thick stratum corneum.