Answer
Melanin is a pigment produced in the melanocytes of the lowest layer of the epidermis, that is, the stratum basale ( or S.germinativum). It is a pigment produced by the oxidation of the amino acid tyrosine. Melanocytes inject melanin into keratinocytes where the pigment granules absorb ultra-violet light and thus protect the nuclei of keratinocytes from damage.There are two types of melanin in the epidermis-- eumelanin (dark-black), and pheomelanin (reddish-brown to yellow) .
Melanins contribute to the color of skin, hair, and eyes ( iris). People without melanin are said to suffer from albinism a condition in which skin, hair and eyes appear pale-yellowish due to the expression of the hues of carotene and hemoglobin in the blood vessels --in eyes and skin.
Work Step by Step
Melanocytes transfer melanin to keratinocytes to protect the latter from damage by UV radiation, but melanocytes themselves are susceptible to injury by UV radiation. Different types of skin cell cancers can be induced by UV damage of cells. However, the most deadly is that induced in melanocytes , the so-called melanoma ; this a very aggressive and deadly form of skin cancer. Albinos are more prone to develop skin cancer than people with normal pigmentation of skin and eyes. To a lesser extent, fair-skinned individuals are at greater risk of skin cancer than dark-skinned individuals: Therefore, the former need to make judicious use of sun screen lotions when extended exposure to sunlight cannot be avoided.
