Which epithelium forms the thick outer layer of the skin (thick skin)?

Which epithelium forms the thick outer layer of the skin (thick skin)?

• A. Simple cuboidal epithelium
• B. Simple squamous epithelium
• C. Keratinized stratified squamous epithelium
• D. Non-keratinized stratified squamous epithelium

Answer: (C)

Thick skin relies on keratinized stratified squamous epithelium to form its outer protective layer. The epidermis is built of multiple layers, and in thick skin the topmost stratum corneum is especially thick. Keratinocytes produce keratin and move outward, eventually becoming cornified and dead, which creates a tough, water-resistant barrier that helps protect against abrasion and prevents excessive water loss on the palms and soles. The other tissue types don’t provide this combination: simple cuboidal epithelium is a single layer of cube-shaped cells typical of glandular lining; simple squamous epithelium is a single flat layer suited for diffusion; non-keratinized stratified squamous epithelium is multi-layered and protective but lacks the keratinized surface needed for the waterproof outer layer of skin.

Thick skin relies on keratinized stratified squamous epithelium to form its outer protective layer. The epidermis is built of multiple layers, and in thick skin the topmost stratum corneum is especially thick. Keratinocytes produce keratin and move outward, eventually becoming cornified and dead, which creates a tough, water-resistant barrier that helps protect against abrasion and prevents excessive water loss on the palms and soles. The other tissue types don’t provide this combination: simple cuboidal epithelium is a single layer of cube-shaped cells typical of glandular lining; simple squamous epithelium is a single flat layer suited for diffusion; non-keratinized stratified squamous epithelium is multi-layered and protective but lacks the keratinized surface needed for the waterproof outer layer of skin.