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Melanocyte function: Influence of cyclic adenosine mono phosphate
Author(s) -
McGuire Joseph
Publication year - 1974
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt1974165part2954
Subject(s) - stratum corneum , endoplasmic reticulum , microbiology and biotechnology , epidermis (zoology) , melanocyte , corneocyte , lamellar granule , chemistry , keratin , hemidesmosome , anatomy , biophysics , biology , ultrastructure , basement membrane , melanoma , paleontology , genetics
The melanocyte is an epidermal cell of specialized function that is derived from the neural crest. Thus, it is close kin with the sympathetic ganglia and cells of the adrenal medulla. The melanocyte resembles a nerve cell in morphology and function. It is characterized by multiple long processes that serve as conduits for its secretory product, melanin, which is passed on to the cells that comprise the fabric of the epidermis, keratinocytes. Keratinocytes as they mature become tightly associated with each other to form a highly impermeable membrane, the stratum corneum, which is the tough outermost layer of the mammalian integument. The epidermis has the paramount function to prevent entry and egress of fluid from the body; this function is served by the stratum corneum alone. The stratum corneum is composed of flattened cells that in their migration outward from the basal layer have lost their nuclei, mitochondria, and endoplasmic reticulum and consist of the fibrillar protein, keratin, combined in some fashion with lipids also synthesized within the epidermal cells. This movement outward from the basal layer to the stratum corneum is an orderly process that takes approximately 2 weeks in the adult human. 9 The arrangement of flattened cells of the stratum corneum is ordered like stacks of polygonal pancakes, with a small overlap between individual cells of adjacent stacks. 22