How many layers of dead, flat keratinocytes are typically found in the stratum corneum?

The stratum corneum is the outermost layer of the epidermis and is primarily composed of dead, flat keratinocytes that have lost their nuclei and cytoplasmic organelles. This layer serves as an essential barrier to protect underlying tissues and prevent water loss.

Typically, the stratum corneum consists of approximately 25 to 30 layers of these flattened cells, which are continually shed and replaced from the layers underneath. The presence of this specific number of layers contributes to the effective barrier function, providing both physical protection against environmental factors and moisture retention.

The correct choice reflects the typical composition of the stratum corneum, emphasizing its role in maintaining skin integrity and health. Other options, while they represent varying layer counts, do not align with the established understanding of the average thickness and composition of the stratum corneum in healthy human skin.