Human hair pigmentation--biological aspects.

摘要: Skin and hair colour contribute significantly to our overall visual appearance social/sexual communication. Despite their shared origins in the embryologic neural crest, follicle epidermal pigmentary units occupy distinct, although open, cutaneous compartments. They can be distinguished principally on basis of former's stringent coupling growth cycle compared with latter's continuous melanogenesis. The biosynthesis melanin its subsequent transfer from melanocyte bulb keratinocytes depend availability precursors a raft signal transduction pathways that are both highly complex commonly redundant. These signalling dependent independent receptors, act through auto-, para- or intracrine mechanisms modified by hormonal signals. many features, follicular melanocytes appear more sensitive than ageing influences. This seen most dramatically greying/canities this is likely reflect significant differences microenvironments. unit may also serve as an important environmental sensor, whereby pigment contributes rapid excretion heavy metals, chemicals toxins body selective binding melanin; rendering fibre useful barometer exposures. recent advanced cell culture methodologies for isolated intact anagen organ should provide research tools necessary elucidate regulatory pigmentation. In longer term, it feasible develop modifiers biological nature accompany those based chemicals.