Findings

Shown here is the urinary bladder with transitional epithelium characteristic of the urinary tract. Note the unique, dome-shaped apical cells next to the bladder lumen. These cells contain a reservoir of membrane that can be mobilized when the bladder fills with urine and the epithelium is stretched.

Comment

The presence of dome-shaped cells helps distinguish transitional epithelium from stratified squamous epithelium of moist mucous membranes.

Preparation

Paraffin section, hematoxylin and eosin

View

Medium-power light microscopy

Specimen

Urinary bladder, non-distended

Image Credit

Katsumi M. Miyai, M.D., Ph.D
Department of Pathology
School of Medicine
University of California, San Diego