What significant process mainly occurs in the stratum corneum?

The stratum corneum is the outermost layer of the epidermis and serves a critical role in the integumentary system. The primary process occurring here is cell death and keratinization. In this layer, skin cells, known as keratinocytes, undergo a specialized form of cell death where they lose their nuclei and cytoplasmic contents, allowing them to become flattened and filled with keratin. This keratinization provides a tough, protective barrier that prevents water loss and shields underlying tissues from environmental damage, such as pathogens and physical abrasions.

Unlike layers beneath the stratum corneum, such as the stratum basale where cell division occurs, or regions involved in melanin production and nutrient absorption, the stratum corneum is primarily concerned with the final steps of cell maturation. The presence of keratin in this layer contributes to the skin's strength and helps the body maintain homeostasis by serving as a barrier to external elements. This understanding emphasizes the importance of the stratum corneum in the overall function and health of the skin.