Urothelial cell

Urothelial cells are specialized epithelial cells that line the urinary tract, including the bladder, ureters, and renal pelvis. They are unique in their ability to stretch and contract, a property that allows them to accommodate fluctuations in urine volume.

Structure

Urothelial cells are stratified into three layers: the basal, intermediate, and superficial (or umbrella) layers. The basal cells are the most undifferentiated and have the ability to proliferate and differentiate into the other cell types. The intermediate cells are larger and more differentiated, while the superficial cells are the largest and most differentiated, with the unique ability to form a barrier that prevents urine from seeping back into the body.

Function

The primary function of urothelial cells is to provide a barrier between the urine and the underlying tissues. They achieve this through the formation of tight junctions and the production of a glycosaminoglycan layer on their surface. This layer is impermeable to water and solutes, preventing the backflow of urine into the bloodstream.

Urothelial cells also play a role in sensation, as they express a variety of receptors and ion channels that allow them to respond to changes in urine volume and composition. This sensory function is thought to contribute to the regulation of micturition.

Clinical significance

Abnormalities in urothelial cells can lead to a variety of conditions. For example, bladder cancer often arises from mutations in these cells. In addition, damage to the urothelium can result in interstitial cystitis, a chronic condition characterized by bladder pain and frequent urination.

Urothelial carcinoma, also known as transitional cell carcinoma, is the most common type of bladder cancer. It is characterized by the presence of cancerous urothelial cells in the bladder, ureters, or renal pelvis.

See also

• Epithelium
• Urinary system
• Bladder cancer
• Interstitial cystitis