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A woman with dark skin. Dark skin is a type of human skin color that is rich in melanin pigments. [1] [2] [3] People with dark skin are often referred to as black people, [4] although this usage can be ambiguous in some countries where it is also used to specifically refer to different ethnic groups or populations. [5] [6] [7] [8]
This is an accepted version of this page This is the latest accepted revision, reviewed on 10 December 2024. "Skin pigmentation" redirects here. For animal skin pigmentation, see Biological pigment. Extended Coloured family from South Africa showing some spectrum of human skin coloration Human skin color ranges from the darkest brown to the lightest hues. Differences in skin color among ...
Melanin is a class of pigment responsible for producing color in the body in places such as the eyes, skin, and hair. The process of melanin synthesis (melanogenesis) starts with the oxidation of l -tyrosine to l-dopa by the enzyme tyrosine hydroxylase , then to l -dopaquinone and dopachrome , which forms melanin.
Melanin (/ ˈ m ɛ l ə n ɪ n / ⓘ; from Ancient Greek μέλας (mélas) 'black, dark') is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. [1] Melanin pigments are produced in a specialized group of cells known as melanocytes.
These stem cells develop into both keratinocyte precursors and melanoblasts - and these melanoblasts supply both hair and skin (moving into the basal layer of the epidermis). There is additionally evidence that melanocyte stem cells are present in cutaneous nerves, with nerve signals causing these cells to differentiate into melanocytes for the ...
The pigment-producing cells that contribute to the yellow spots of some sub-species are called xanthophores. [30] It appears that the fully-black phenotypes do not ever develop these xanthophores. [31] Alpine salamanders produce a toxin from their skin, and both fully melanistic, black salamanders and spotted individuals produce the compound. [32]
It is called neuromelanin because of its function and the color change that appears in tissues containing it. It contains black/brown pigmented granules. Neuromelanin is found to accumulate during aging, noticeably after the first 2–3 years of life. It is believed to protect neurons in the substantia nigra from iron-induced oxidative stress.
The physical appearance of each type is briefly described, including colour adjectives referring to skin and hair colour: rufus "red" and pilis nigris "black hair" for Americans, albus "white" and pilis flavescentibus "yellowish hair" for Europeans, luridus "yellowish, sallow", pilis nigricantibus "swarthy hair" for Asians, and niger "black ...