787 pages on this wiki. Mark Andrew Spitz (born February 10, 1950) is a retired American swimmer. He won seven gold medals at the 1972 Summer Olympics, an achievement only surpassed by Michael Phelps who won eight golds at the 2008 Olympics.Spitz set new world records in all seven events in which he competed, a record that still stands.87 pages on this wiki. Mark Andrew Spitz (born February 10, 1950) is a retired American swimmer. He won seven gold medals at the 1972 Summer Olympics, an achievement only surpassed by Michael Phelps who won eight golds at the 2008 Olympics.
The colour of the skin is determined by the concentrations of three main pigments: melanin, carotene and haemoglobin. These are found in the dermis and combine to produce the pigmentation of all surface tissues including the skin, mucous membranes, and even the eyes.
They are located in the stratum basale, but branch out between the keratinocytes in suprabasal layers. About 5-10 % of the cells in the epidermis are melanocytes. The main purpose of melanocytes is the production of melanin, the protein responsible for the pigmentation of the skin, eyes, and hair. Melanin protects the cells in the skin and in deeper layers from the hazardous effects of UV radiation.