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Hair shafts. Coloured scanning electron micrograph (SEM) of hairs (yellow) emerging from skin. Some of the hairs have been cut, for example at top right. The surrounding layer of skin (orange) has a typically uneven surface. Hairs grow from follicles in the underlying layer of the skin (the dermis). The portion of the hair protruding from the skin is made up of dead tissue, largely the protein keratin. Hair grows at around one centimetre every month. Magnification unknown. (KEYSTONE/SCIENCE PHOTO LIBRARY/STEVE GSCHMEISSNER)