Transitional epithelium (urothelium)
 

• This type of epithelium is found only in the urinary tract and is also called urothelium. It is highly specialized to resist the toxic effects of urine and to stretch.

• Look at this image of the bladder to the right, where you can see that transitional epithelium is a stratified epithelium, several layers thick, with characteristic rounded or umbrella shaped cells lining its superficial surface (arrows).

• This type of epithelium is called transitional because it appears to get thinner and its cells flatten as the organ becomes distended with urine.

• Examine the folded lining of the urinary bladder, trichrome stain, urinary bladder H&E stain, as well a section of ureter (scan the slide to find the ureter as shown in the image at the right). The most distinguishing feature is that most of the superficial cells are rounded or umbrella shaped.
   

Intercellular junctions and cell-extracellular matrix junctions.