Melanocyte
Definition
Melanocytes are specialized cells located in the basal layer of the epidermis that produce melanin, the pigment responsible for skin, hair, and eye color. Each melanocyte services approximately 36 keratinocytes in what is called the 'epidermal melanin unit.' Melanocytes produce melanin within organelles called melanosomes, which are then transferred to surrounding keratinocytes via dendrites (arm-like extensions). This distribution of melanin throughout the epidermis provides protection against UV radiation. All humans have roughly the same number of melanocytes regardless of skin color — differences in skin tone result from variations in the size, number, type, and distribution of melanosomes rather than melanocyte count. Disorders of melanocytes include vitiligo (loss of melanocytes causing white patches), melanoma (cancer of melanocytes), and various forms of hyperpigmentation (overactive melanin production).
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