Final answer:
The stratum corneum cells originate from the stratum basale, which is the deepest layer of the epidermis consisting of basal stem cells that produce keratinocytes, eventually forming the outer skin layer after a process of differentiation and migration towards the surface.
Step-by-step explanation:
The cells of stratum corneum were initially produced in the stratum basale, also known as the stratum germinativum. This deepest layer of the epidermis is primarily made of basal cells, which are cuboidal-shaped stem cells. These basal cells are precursors of the keratinocytes that make up the epidermis. As these cells undergo mitosis, new keratinocytes are formed, and older ones are pushed towards the surface, eventually becoming part of the stratum corneum. The stratum basale not only gives rise to keratinocytes but also houses melanocytes, which produce the pigment melanin responsible for skin color and protection against UV radiation.
Along with the stratum basale, other layers such as the stratum spinosum, stratum granulosum, and in some areas the stratum lucidum, contribute to the development and differentiation of cells that end up in the stratum corneum. This outermost layer provides a barrier to infection, prevents dehydration, and offers mechanical protection. Over about 4 weeks, the entire stratum corneum is replaced as cells are shed and replaced by newer cells from the lower strata.