What is the main characteristic of the stratum corneum?

The main characteristic of the stratum corneum is that it consists of dead cells that are constantly shed. This outermost layer of the epidermis is composed of keratinized cells, which means the cells have lost their nuclei and are filled with keratin, a protective protein. This arrangement serves an important function in providing a barrier to water loss and protecting the underlying layers of skin from environmental damage, pathogens, and physical abrasions.

The stratum corneum is not the thickest layer of the skin; that title goes to the dermis, which sits beneath the epidermis. It is not involved in cell growth, as that process primarily occurs in the deeper layers of the epidermis, particularly in the stratum basale and stratum spinosum. Finally, sensory nerve endings are primarily located in the dermis, not in the stratum corneum, which is more concerned with protection than sensation.