What does keratinized epithelium do?

• A. It causes a water barrier.
• B. It increases mucous production.
• C. It indicates a lack of epidermis.
• D. It forms cartilage.

Answer: (A)

Keratinized epithelium forms a tough, dry outer layer that prevents water loss and protects deeper tissues. In the skin, keratinocytes produce keratin and migrate toward the surface, where they die and become packed with keratin in the outermost cornified layer. This dead, keratin-rich layer, aided by lipid-rich material released into the spaces between cells, creates a waterproof barrier that minimizes dehydration and shields against abrasion. Mucous production isn’t a feature of keratinized skin; that function is associated with mucous membranes that keep surfaces moist. Keratinized epithelium is part of the epidermis, not a sign of missing epidermis. Cartilage formation, on the other hand, is a job of connective tissue derived from mesenchyme, not epithelial tissue.