Skin pigmentation

The keratinocytes are not the only cells in the epidermis.

The melanocytes of the epidermis are crucial in determining skin pigmentation (color).

The distribution of melanin in the epidermis.

    There are two forms of the pigment melanin: eumelanin granules, which tend to be round and smooth and produce black and brown skin pigmentation, and phaeomelanin granules, which are more irregular in shape and which are more prominent in lighter skins, particularly in association with red hair and freckles.
    These two forms of melanin are often both present together, and occur in varying proportions.

    Among the most important of these cells are the melanocytes, which are found in the basal layer of the epidermis. These manufacture a special pigment called melanin, which helps to determine the hair and skin pigmentation. The pigment is made on tiny structures called melanosomes, which aggregate as granules and are delivered in small 'packages' to each basal cell by slender filaments called dendrites. One melanocyte supplies about 36 keratinocytes with melanin granules. These tiny packages of pigment sit over the nucleus - the vital centre of the cell - in every cell in the epidermis, and protect it from the harmful rays of the sun.