Skin. Coloured scanning electron micrograph of a section through the human skin. The uppermost layers of the skin (pink and red) make up the epidermis. The surface of the epidermis (at top, pink) is the cornified layer composed of flattened, fused keratin-rich cell remnants. The dead cells from this layer are continuously being shed and replaced from cells from the living epidermal layers below (red). These layers contain keratinocytes, specialized cells that synthesize keratin. The lowest layer shown here is the dermis (yellow). The dermis is a thick layer of fibrous connective tissue which supports and nourishes the epidermis. Magnification: unknown.