Complex sentence: Differentiating cells delaminate from the basement membrane and are displaced outwards through the epidermal layers, undergoing multiple stages of differentiation until, in the stratum corneum, losing their nucleus and fusing to squamous sheets, which are eventually shed from the surface (desquamation).
Split into simpler sentences: Differentiating cells delaminate from the basement membrane and are displaced outwards through the epidermal layers. In the stratum corneum the cells lose their nucleus and fuse to squamous sheets, which are eventually shed from the surface (desquamation).