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Melanocytes are melanin-producing neural crest-derived [3] cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), [4] the inner ear, [5] vaginal epithelium, [6] meninges, [7] bones, [8] and heart found in many mammals and birds. [9] Melanin is a dark pigment primarily responsible ...
In humans, they constitute 90% of epidermal skin cells. [1] Basal cells in the basal layer ( stratum basale ) of the skin are sometimes referred to as basal keratinocytes . [ 2 ] Keratinocytes form a barrier against environmental damage by heat , UV radiation , water loss , pathogenic bacteria , fungi , parasites , and viruses .
Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris. [1] [2] [3]: 854 People with darker skin tones are more prone to hyperpigmentation, especially with excess sun exposure. [4] Many forms of hyperpigmentation are caused by an excess production of melanin. [4]
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 January 2025. "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 ...
Freckles are clusters of concentrated melaninized cells which are most easily visible on people with a fair complexion.Freckles do not have an increased number of the melanin-producing cells, or melanocytes, but instead have melanocytes that overproduce melanin granules (melanosomes) changing the coloration of the outer skin cells (keratinocytes).
Poikiloderma is a skin condition that consists of areas of hypopigmentation, hyperpigmentation, telangiectasias and atrophy. Poikiloderma of Civatte is most frequently seen on the chest or the neck, characterized by red colored pigment on the skin that is commonly associated with sun damage.
They have a dominant gene that causes hyperpigmentation (Fibromelanosis), making the chicken entirely black; including feathers, beak, and internal organs. Melanism in feral rock doves are actually quite common,to some extent, especially if the area is abundant with the species. The amount of pigmentation is varied, from a slight darker ...
Melasma (also known as chloasma faciei, [1]: 854 or the mask of pregnancy [2] when present in pregnant women) is a tan or dark skin discoloration.Melasma is thought to be caused by sun exposure, genetic predisposition, hormone changes, and skin irritation. [3]