Which epithelium lines the urinary tract?

Study for the CAMLPR Histology Practice Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

The urinary tract is lined by transitional epithelium because it must stretch as urine fills the bladder and then recoil. This tissue, also called urothelium, is multi-layered with dome-shaped umbrella cells on the surface and tight junctions that create a watertight barrier. When the organ relaxes, the cells look more cuboidal or columnar; as it stretches, the cells flatten but the layer remains intact and impermeable to urine. Simple squamous would not provide the necessary barrier or stretch, since it’s optimized for diffusion. Pseudostratified ciliated epithelium is typical of the respiratory tract, not the urinary tract. Stratified squamous handles abrasion in areas like the esophagus or vagina, but it doesn’t accommodate the repeated distension of the urinary tract. Thus transitional epithelium best fits lining the urinary tract.