Which type of epithelial cell is exclusively found in the urinary system?

Transitional cells are specialized epithelial cells that are specifically adapted to the unique conditions of the urinary system. These cells are primarily found in the bladder, ureters, and parts of the urethra. The defining characteristic of transitional epithelium is its ability to change shape in response to stretching. When the bladder fills with urine, these cells can flatten and become more squamous-like to accommodate the increased volume. Conversely, when the bladder is empty, the cells can return to a more cuboidal shape.

This transitional feature allows for an effective barrier against the toxic effects of urine, as well as contributes to the elasticity of the urinary bladder. The presence of transitional cells is a crucial adaptation for the function of the urinary system, enabling it to expand and contract without losing its structural integrity or allowing leakage. Other types of epithelial cells, such as cuboidal, columnar, and squamous cells, serve different functions and are found in other tissues but are not characteristic of the urinary system.