Stratified squamous, keratinized (dry) epithelium
A second type of stratified squamous epithelium is keratinized, and forms the outer layer of the skin (epidermis) which is exposed to the dry external environment. In this location, it not only needs to provide robust protection against abrasion, but also aid in preventing desiccation. To create this barrier, cells produced at the basal surface accumulate filaments of keratin protein and undergo a specialized form of cell death that generates a tough, protective barrier of dead cells (squames) at the surface, composed almost entirely of the keratin. 100x
Stratified squamous, keratinized (dry) epithelium
A second type of stratified squamous epithelium is keratinized, and forms the outer layer of the skin (epidermis) which is exposed to the dry external environment. In this location, it not only needs to provide robust protection against abrasion, but also aid in preventing desiccation. To create this barrier, cells produced at the basal surface accumulate filaments of keratin protein and undergo a specialized form of cell death that generates a tough, protective barrier of dead cells (squames) at the surface, composed almost entirely of the keratin. 100x
- Living cells >
Cells passing upwards in the epithelium accumulate keratin filaments, eventually losing all their contents, except for the keratin. Multiple layers of these flattened, dead cells (squames) form the surface of the epithelium. This process does not occur in non-keratinized epithelia where surface cells alive.
- Dead cells (squames) >
The surface cells are squamous shaped and provide a dry surface for the epithelium.
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