(cornification) n. the process by which cells become horny due to the deposition of *keratin within them. It occurs in the *epidermis of the skin and associated structures (hair, nails, etc.), where the cells become flattened, lose their nuclei, and are filled with keratin as they approach the surface.
n. the outer layer of the *skin, which is divided into four layers (see illustration). The innermost Malpighian or germinative layer (stratum germinativum) consists of continuously dividing cells. The other three layers are continually renewed as cells from the germinative layer are gradually pushed outwards and become progressively impregnated with keratin (see keratinization). The outermost layer (stratum corneum) consists of dead cells whose cytoplasm has been entirely replaced by keratin. It is thickest on the soles of the feet and palms of the hands. —epidermal adj.... epidermis
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