The term ‘melanocyte’ is derived from the Greek words melas and kutos, which mean ‘black’ and ‘cell’, and refers to an element constituting the epidermis. It is responsible for the skin colouration. Although they are at the origin of our tan, melanocytes mainly have a preventive function against the harmful effects of too long exposures to the sun.
A melanocyte is a cell of neural origin. It is formed in the basal layer of the epidermis, but it is also found in the iris of the eyes and at the top of hair follicles. The number of melanocytes varies depending on the body area.
If melanocytes colour the skin, it is to protect the epidermis from UV rays. They work a little like ‘cell radars'. When the skin is exposed to the sun, they synthesize melanin (brown pigment): that is melanogenesis.
Melanin is contained in an organite (element contained in the cells), which is called melanosome. Then, this substance is captured by the keratinocytes to protect the skin.
Every melanocyte distributes melanin to 36 keratinocytes.
Although melanocytes are undeniably useful in protecting the epidermis from the sun, sometimes they start making melanin without the contribution of solar photons, which can trigger the formation of spots on the skin.
JS© CosmeticOBS-L'Observatoire des Cosmétiques