urothelial cell umbrella cell of urothelium 2023-06-16T07:59:43Z Umbrella cells are attached to sub-superficial cell layers via desmosomes, while tight junctions localized between superficial cells aid in forming a high-resistance barrier function. Another distinguishing feature of an umbrella cell type is the presence of subapical discoidal/fusiform-shaped vesicles contributing to the plasticity in urothelial cell surface area through a regulated process of endocytosis/exocytosis. It has been noted in at least some mammalian species that the urothelial umbrella cell type expresses UPK1A, UPK1B, UPK2 and UPK3A. Unlike intermediate and basal cells of the urothelium, CK17 is reported to be completely absent and p63 not expressed in umbrella cells. facet cell of urothelium FMA:84149 https://orcid.org/0000-0003-3065-9183 superficial cell of urothelium A urothelial cell that is terminally differentiated and part of the urothelial apical surface that forms the high-resistance barrier of urothelium. Umbrella cells have been described as the largest of urothelial cell types, highly polarized, and, in some species, multinucleated. In the relaxed state, these cells form a dome-shaped structure at the apical pole and can also cover multiple underlying intermediate cells, leading to the name umbrella cells. In contrast, these cells flatten when the bladder is filled. Homo sapiens