The cells in this layer are filled with a protein called keratin . Keratin is a very interesting protein because it is tough - horns, hair, hoofs, fingernails and feathers all gain their strength from keratin. That is what makes your skin so tough. In parts of the body that get a lot of wear, like the palms and the feet, the stratum corneum is thicker to handle the abrasion. Living among the basal cells in the malpighian layer is another type of cell called a melanocyte .
Melanocytes produce melanin , which is a pigment that is the source of tanning.
The melanocytes are actually where a tan comes from. In the main, however, it is determined by melanin, a pigment manufactured by dendritic cells called melanocytes, found among the basal cells of the epidermis. Colour differences are due solely to the amount of melanin produced and the nature of the pigment granules. When the skin becomes tanned on exposure to sunlight, the melanocytes do not increase in number, only in activity. Not only do melanocytes produce a tan, they are also responsible for the form of cancer called melanoma.