where is vitamin d synthesized in the skin
Vitamin D The skin consists of two primary layers: the inner layer called the dermis, composed largely of connective tissue, and the outer, thinner epidermis.[162] Thick epidermis in the soles and palms consists of five strata; from outer to inner, they are: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Vitamin D is produced in the keratinocytes[163] of two innermost strata, the stratum basale and stratum spinosum.[160]
Melanocyte 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.[9] Melanin is a dark pigment primarily responsible for skin color. Once synthesized, melanin is contained in special organelles called melanosomes which can be transported to nearby keratinocytes to induce pigmentation. Functionally, melanin serves as protection against UV radiation. Melanocytes also have a role in the immune system.