Which epidermal layer is primarily responsible for water retention due to keratin-filled cells?

Which epidermal layer is primarily responsible for water retention due to keratin-filled cells?

• A. Stratum basale
• B. Stratum spinosum
• C. Stratum granulosum
• D. Stratum corneum

Answer: (D)

Water retention in the skin is mainly due to the outermost epidermal layer. This layer is made up of corneocytes—dead, flattened cells filled with keratin—that have lost their nuclei and organelles. These keratin-rich cells form a dense, tough barrier, and they sit in a lipid-rich matrix that fills the spaces between them. Together, the keratin-filled corneocytes and the surrounding lipids create a highly effective waterproof seal that minimizes water loss from the body. Deeper layers are involved in making keratin and contributing to barrier formation, but the primary water-retaining function comes from the stratum corneum.

Water retention in the skin is mainly due to the outermost epidermal layer. This layer is made up of corneocytes—dead, flattened cells filled with keratin—that have lost their nuclei and organelles. These keratin-rich cells form a dense, tough barrier, and they sit in a lipid-rich matrix that fills the spaces between them. Together, the keratin-filled corneocytes and the surrounding lipids create a highly effective waterproof seal that minimizes water loss from the body. Deeper layers are involved in making keratin and contributing to barrier formation, but the primary water-retaining function comes from the stratum corneum.