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.
1 Melanocyte stem cells are responsible for regeneration of melanocytes, a type of pigment cell. 2  Melanocytes produce the pigment melanin, and therefore play an important role in skin and hair follicle pigmentation. 3  It is not yet certain where these stem cells are found in humans.hey are responsible for constant renewal (regeneration) of your skin, and for healing wounds. So far, scientists have identified several different types of skin stem cell: 1  Epidermal stem cells are responsible for everyday regeneration of the different layers of the epidermis.