Keratinocytes: Overview

Synonyms

Basal keratinocytes; Corneocytes; Cornified keratinocytes; Granular keratinocytes; Horn cells; Spinous keratinocytes; Squamous cells (James et al. 2011; Adkinson et al. 2014)

Definition

Keratinocytes are the principal cells of the epidermis, derived from the ectoderm, whose main function is to produce keratin and provide a physical and immunological barrier against the outside environment (James et al. 2011).

Structure

Keratinocytes are the most abundant cell in the epidermis (90%) with a life cycle of approximately 28 days. They are continually renewing cells that can be divided into four types based on the epidermal layer in which they exist: basal, spinous, granular, and cornified. Basal keratinocytes are attached to the basement membrane by hemidesmosomes. A change in keratin composition of these cells precedes their differentiation into spinous keratinocytes, so named for their unique keratin cytoskeleton. The expression of lamellar granules containing the precursors of...