Introduction
Melanin is a color pigment and therefore responsible for our skin color, hair color and the color of our eyes. Depending on how much melanin these structures contain, we have a lighter or darker skin type. Besides melanin, heredity also plays a role here. Melanin is produced from an amino acid with the help of UV rays and a hormone in our body.
Function of melanin
Melanin is a pigment that is responsible for coloring skin, hair and the color pigments in the eye. Two different melanins are distinguished in humans. There is the brown-blackish eumelanin and the yellowish-reddish pheomelanin.
Usually the melanins occur as mixed forms. The content and the ratio of the two melanins play an important role in the color of the hair. The production of melanin is increasingly stimulated by sunlight and a melanocyte stimulating hormone.
The pigment assumes an important protective function, especially in the human skin. The brownish to black color pigment protects the epidermis from harmful UV rays of the sun. The sun’s rays cause increased accumulation of melanin in the skin.
The more melanin is produced by the melanocytes, the darker the skin color appears. This is finally transferred to keratinocytes (mainly occurring skin cells) and stored in them. The melanin wraps itself around the nucleus (which also contains the genetic material, the DNA) of the keratinocytes to protect them from the cell-changing sun rays.
UV rays can damage the genetic material, causing cells to degenerate and cancer to develop. Melanin therefore acts as a kind of natural “UV protection”. This UV protection exists already short time after the skin was exposed to sunbeams and the Melaninproduktion rose.
Melanin does not have to be manufactured however always completely again, since already some provisional products are present in the skin, so that Melanin can be brought with short time sun exposure relatively fast into the Keratinozyten. This so-called immediate pigmentation, however, fades after a few days, whereas a late pigmentation of the skin due to prolonged exposure to the sun, the tan lasts longer and also offers longer protection. Melanin also takes over the coloration of the iris in the eyes.
Depending on the level of melanin in the iris, different eye colors are created. The inheritance of genes also plays a role here. If the pigments in the iris and in the choroid are missing, the blood vessels shine through and the classic picture of albinism (red eyes) develops.
