False-colour scanning electron micrograph (SEM) of the surface of skin from the human scalp, showing the emergence of three hairs through the flattened layers of epidermal cells. The worm-like hair at left has just emerged; the 2 finer hairs are older. Hair is covered by a cuticle consisting of highly flattened cells that overlap each other. The structure of skin varies according to its location; a distinction is made between the thick skin that covers the hands & feet and thin skin that covers most of the remaining body surface. The ability of skin to differentiate gives rise to hair, nails, sebaceous glands & sweat glands. Magnification: x100 at 35mm size.