Which statement correctly defines the stratum corneum?

Which statement correctly defines the stratum corneum?

• A. The stratum corneum is the deepest layer of the epidermis
• B. The stratum corneum is the outermost horny layer
• C. The stratum corneum contains actively dividing cells
• D. The stratum corneum is part of the dermis

Answer: (B)

The stratum corneum being the outermost horny layer of the epidermis is the key idea. It consists of flattened, dead keratinocytes that have keratinized and lost their nuclei, creating a tough barrier that protects against injury and prevents water loss. Because these cells are dead, they do not divide—that activity occurs in the deepest epidermal layer, the stratum basale. The stratum corneum is part of the epidermis, not the dermis, which lies beneath. This combination—outermost position, horny (keratinized) cells, and lack of active division—is why the statement describing it as the outermost horny layer is correct.

The stratum corneum being the outermost horny layer of the epidermis is the key idea. It consists of flattened, dead keratinocytes that have keratinized and lost their nuclei, creating a tough barrier that protects against injury and prevents water loss. Because these cells are dead, they do not divide—that activity occurs in the deepest epidermal layer, the stratum basale. The stratum corneum is part of the epidermis, not the dermis, which lies beneath. This combination—outermost position, horny (keratinized) cells, and lack of active division—is why the statement describing it as the outermost horny layer is correct.