What is the primary function of the stratum corneum?

The primary function of the stratum corneum, which is the outermost layer of the epidermis, is to act as a barrier that protects the underlying layers of the skin. This layer is composed of dead skin cells that have become keratinized, forming a tough protective layer. It prevents the loss of moisture and protects against environmental hazards such as bacteria, chemicals, and physical abrasions. The integrity of the stratum corneum is essential for maintaining overall skin health and preventing dehydration.

The stratum corneum’s structure allows it to effectively shield the living skin layers beneath it from potential harm, while its lipid content helps to maintain hydration by reducing transepidermal water loss. This protective function is crucial for skin resilience and overall integrity.

The other choices do not accurately capture the primary role of the stratum corneum. Regulating skin temperature is mainly a function of deeper layers involved in perspiration and blood flow. Nourishing skin cells primarily occurs in the underlying layers where living cells are present, and the production of sweat and oil is also localized to specific structures within the skin rather than the stratum corneum itself.