Final answer:
The stratum basale is the deepest layer of the epidermis responsible for regenerating the most superficial layers through the division of stem cells. These new cells migrate upwards, eventually forming the outer stratum corneum, which continuously sheds and is renewed.
Step-by-step explanation:
Within the layers of the epidermis, the stratum basale is crucial for the regeneration of the epidermis. This layer is the deepest part of the epidermis and contains stem cells that divide to create new keratinocytes, the predominant cell type in the epidermis. As these new keratinocytes are formed, they push up through the layers above, including the stratum spinosum and the stratum granulosum, eventually reaching the outermost layer called the stratum corneum.
The stratum corneum is composed of flat, dead keratinocytes that provide a tough, protective barrier. These cells are shed periodically and replaced by new cells originating from the stratum basale. Thus, although the stratum spinosum is situated above the stratum basale, it is the latter that is primarily responsible for the regeneration of the epidermis, continuously supplying new cells to replace the shed cells of the stratum corneum.