What type of skin cell layer is responsible for the protective barrier of the skin?

The stratum corneum is the outermost layer of the epidermis and serves as the primary protective barrier of the skin. This layer consists of dead keratinized cells that are continuously shed and replaced. The cells in the stratum corneum are rich in keratin, a tough, fibrous protein that strengthens the skin and helps prevent water loss, as well as protecting against environmental factors, such as pathogens and harmful substances.

In contrast, the stratum basale is the deepest layer of the epidermis responsible for generating new skin cells, while the stratum granulosum contains cells that begin the process of keratinization. The stratum lucidum is an additional layer found only in thick skin areas, such as the palms and soles, and offers some protection but is not the primary barrier. Overall, the stratum corneum's structure and composition make it essential for maintaining the skin's integrity and function as a barrier.