Melanin is the protein that gives skin its pigment.
Melanin, a complex polymer derived from the amino acid tyrosine, is responsible for the wide range of skin, hair, and eye colors seen in humans. Specialized cells called melanocytes produce melanin within organelles called melanosomes. These melanosomes are then transferred to keratinocytes, the predominant cell type in the epidermis (outer layer of skin), effectively distributing the pigment.
Here's a breakdown of key aspects related to melanin and skin pigmentation:
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Types of Melanin: There are primarily two types of melanin:
- Eumelanin: Responsible for brown and black pigments. Higher concentrations lead to darker skin tones.
- Pheomelanin: Responsible for red and yellow pigments. Higher concentrations contribute to lighter skin tones and red hair.
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Melanocyte Activity: The amount and type of melanin produced by melanocytes determine an individual's skin pigmentation. This activity is influenced by genetic factors, as well as environmental factors like exposure to ultraviolet (UV) radiation from the sun.
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UV Protection: Melanin acts as a natural sunscreen, absorbing harmful UV radiation and protecting the underlying skin cells from DNA damage. This is why exposure to sunlight stimulates melanocytes to produce more melanin, resulting in tanning.
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Conditions Affecting Pigmentation: Various conditions can affect melanin production and distribution, leading to changes in skin pigmentation:
- Vitiligo: An autoimmune disorder where melanocytes are destroyed, resulting in patches of skin that lose their pigment.
- Albinism: A genetic condition characterized by a partial or complete absence of melanin in the skin, hair, and eyes.
- Melasma: A condition characterized by dark patches on the face, often associated with hormonal changes during pregnancy.
In summary, melanin, a protein produced by melanocytes, is the primary determinant of skin color and plays a crucial role in protecting the skin from UV damage. The type and amount of melanin produced, along with its distribution within the skin, determine the diverse range of skin tones observed in humans.
