Which layer of the epidermis is characterized predominantly by dead and dying keratinocytes?

The epidermis consists of several layers, and the layer predominantly composed of dead and dying keratinocytes is the stratum corneum. This outermost layer serves as a crucial barrier to protect the underlying tissues from environmental damage, pathogens, and water loss. Keratinocytes in the stratum corneum are filled with keratin, a protein that provides structural strength and waterproofing. As these cells move upwards from the deeper layers of the epidermis, they gradually lose their nuclei and organelles, resulting in the characteristic appearance of dead cells that form the protective layer.

The stratum granulosum contains keratinocytes that are in the process of dying and beginning to accumulate keratohyalin granules, which contribute to the keratinization process but do not consist mainly of dead cells. The stratum lucidum, found only in thick skin areas such as palms and soles, is also characterized by flattened cells but is primarily a transitional layer between living and dead cells. The stratum basale, being the deepest layer, consists of actively dividing cells that are responsible for producing new keratinocytes. Thus, while other layers have their unique characteristics, it is the stratum corneum that fulfills the role of providing a layer predominantly