Which skin layer is an anuclear cell layer that is thick and contains flattened cells filled almost entirely with keratin filaments?

• A. Stratum Granulosum
• B. Stratum Spinosum
• C. Stratum Corneum
• D. Stratum Basale

Answer: (C)

The described layer is the outermost epidermal layer, made of dead, flattened cells that have lost their nuclei and are filled with keratin filaments. These corneocytes are packed tightly, forming a thick, durable barrier at the surface of the skin. This is the result of keratinization, which produces a hard, anuclear layer that protects against water loss and environmental insults.

Beneath it, keratinization begins in the granular layer, where cells still have nuclei and accumulate keratohyalin granules. In the spinosum, living keratinocytes with desmosomes form several layers, and the basale is a single layer of actively dividing cells at the dermal–epidermal boundary. Thus, the thick, anuclear, keratin-filled outer layer is the Stratum Corneum.