What is primarily responsible for producing new epidermal cells?

The stratum germinativum, also known as the basal layer of the epidermis, is primarily responsible for producing new epidermal cells. This layer is where keratinocytes, the predominant cell type in the epidermis, undergo mitosis and produce new cells. As these new cells are generated, they push older cells up through the various layers of the epidermis, leading to the formation of the protective outer layers.

The stratum corneum is the outermost layer of the skin and consists of dead, flattened keratinized cells that provide a barrier to water loss and environmental damage but does not produce new cells. The stratum lucidum is a thin layer found only in thick skin areas, such as the palms and soles, and serves mainly to provide an additional barrier but does not participate in cell production. The stratum granulosum, while important for the process of keratinization, does not generate new cells; instead, it is where cells begin to transition from living to dead keratinized cells. Thus, the stratum germinativum is integral to the renewal and maintenance of the epidermis.