What is the primary function of the stratum corneum?

The stratum corneum is the outermost layer of the skin and serves as a vital protective barrier. Its primary function is to prevent the loss of moisture and protect underlying tissues from environmental damage, pathogens, and chemicals. Composed of dead skin cells that are continuously shed and replaced, the stratum corneum plays a crucial role in maintaining skin integrity.

This layer helps to keep the skin hydrated by minimizing water loss while also protecting against external aggressors such as bacteria and irritants. Additionally, the thickness of the stratum corneum can vary depending on the area of the body and can adapt based on environmental factors, further showcasing its protective role.

While the other options relate to functions of the skin, they do not specifically pertain to the stratum corneum's primary purpose. Temperature regulation is managed by deeper layers and helps the skin react to environmental changes. Absorption of nutrients typically occurs at deeper levels of the skin, while sensation is facilitated by nerve endings present in other layers as well. Thus, the protective barrier function of the stratum corneum remains its key and most critical role.