Video - Ureter, bladder and urethra histology

The histology of the ureters, bladder, and urethra share some common features, such as the concentric layers of transitional epithelium, lamina propria, muscularis externa, and adventitia. The transitional epithelium of these organs is composed of three layers, including a superficial layer with umbrella cells, an intermediate layer of cuboidal and low columnar cells, and a single layer of basal cells.

The muscularis externa of the ureters has an inner longitudinal layer and a circular outer layer of smooth muscle, while the distal ureters, bladder, and proximal urethra have an additional outer layer of longitudinal smooth muscle. Both males and females have a distal urethra lined with stratified squamous epithelium, but only males have pseudostratified and stratified columnar epithelium, which is found in the membranous and spongy portions of the urethra.