Slide 15. Transitional epithelium of the urinary bladder, H&E
Explains how transitional epithelium of the urinary bladder looks in H&E-stained sections, covering the stain colours and how the layers change between an empty and a stretched bladder. It describes the basal, intermediate and dome-shaped surface cells, including binucleated umbrella cells with a thick pink top edge. It also notes the absence of keratin and cilia and contrasts the surface with stratified squamous non-keratinised epithelium.
Inside: 1 section · 1 min
Topic 104 of 127 in the MU Sofia syllabus for Cytology (Dental Medicine, Year 1). The free AceMed note covers it in 1 section, about 106 words (1 min of reading).
In this note
Introduction
Introduction
The bladder is lined by transitional epithelium (urothelium), a stratified epithelium that changes its shape as the bladder fills and empties.
Stain
H&E: nuclei blue-purple, cytoplasm pink.
How to recognise it
In an empty bladder, many layers: cuboidal basal cells, polygonal intermediate cells and large surface cells.
The surface umbrella (dome) cells bulge into the lumen. Some have two nuclei, and their top edge is thick and pink.
In a stretched bladder, only 2–3 layers, with flattened surface cells.
No keratin and no cilia.
Don't confuse it with: stratified squamous non-keratinized epithelium, whose surface cells are flat rather than dome-shaped.
Theory: topic 38 (stratified surface epithelia).
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