Assertion: epithelium's cell | /r/CapableOf | lose their nucleus
Facets:
Source sentences:
text: The cells lose their nucleus and cytoplasm, and instead contain a tough protein called keratin which has waterproof properties.
text: Differentiating cells delaminate from the basement membrane and are displaced outward 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).