Melanin, the pigment responsible for hair color, is produced by melanocytes located in the upper hair matrix of the anagen hair follicle.
Understanding Hair Pigmentation
Hair color is determined by the type and amount of melanin present. The process begins within the hair follicle. Specifically:
- Melanocytes: Specialized cells called melanocytes reside in the upper hair matrix of the anagen (growth) phase of the hair follicle. These cells are responsible for producing melanin.
- Melanin Transfer: The produced melanin is then transferred primarily to the hair shaft cortex, with lesser amounts going to the medulla, and rarely to the cuticle. This explains why the cortex is the main determinant of overall hair color.
Types of Melanin and Their Impact on Hair Color
Two main types of melanin contribute to hair color:
- Eumelanin: This type produces brown and black colors. An abundance of eumelanin leads to darker hair.
- Pheomelanin: This type creates red and yellow tones. Higher levels of pheomelanin result in lighter and redder hair.
The relative amounts of these two melanins determine the final hair color. The decrease or cessation of melanin production leads to graying hair.
Examples:
- Black hair: High levels of eumelanin.
- Brown hair: A mix of eumelanin and some pheomelanin.
- Red hair: High levels of pheomelanin and relatively low levels of eumelanin.
- Blond hair: Low levels of both eumelanin and pheomelanin.
- Gray hair: Reduced or absent melanin production.
The information provided supports the statement that melanocytes in the upper hair matrix of the anagen hair follicle are responsible for melanin production, which directly impacts hair color. Conditions like albinism result from a deficiency in melanin production, further highlighting the crucial role of melanocytes. The aging process also affects melanin production, leading to graying hair.
