Massachusetts Board of Cosmetology Practice Exam

The stratum corneum serves the crucial function of protecting the underlying layers of skin. It is the outermost layer of the epidermis, comprised of dead skin cells that are continually shed and replaced. This layer acts as a barrier against environmental hazards, such as pathogens, chemicals, and physical abrasions. By preventing moisture loss and blocking harmful substances from penetrating deeper into the skin, the stratum corneum plays a key role in maintaining skin health and integrity.

While the other functions mentioned—such as producing hair follicles, absorbing vitamins, and regulating body temperature—are important in the overall function of the skin, they are not characteristics of the stratum corneum. Specifically, hair follicles are located in deeper layers of the skin, and while the skin does participate in vitamin absorption and temperature regulation, these functions are attributable to other skin components and systems, not the stratum corneum itself.