Final answer:
The lifecycle of a keratinocyte from its creation in the stratum basale to shedding from the stratum corneum takes about 48 days, with an additional 4 weeks spent as part of the protective outer skin layer.
Step-by-step explanation:
The journey of a keratinocyte from the stratum basale to the stratum corneum is a crucial process in the regeneration of our skin. The stratum basale is home to the stem cells responsible for the creation of new keratinocytes. As these cells are produced, they begin a migration towards the skin's surface, transitioning through layers such as the stratum spinosum and stratum granulosum, where they start to fill with keratin and die off. The entire lifecycle of a keratinocyte from formation to shedding takes approximately 48 days. The stratum corneum, composed of these dead keratinized cells, provides a vital barrier to protect from microbes, dehydration, and mechanical damage. Over a period of about 4 weeks, these cells are naturally sloughed off, and cosmetic procedures like microdermabrasion can accelerate this exfoliation.