What type of epithelial tissue lines the urinary bladder?

The urinary bladder is lined with transitional epithelium, a specialized type of tissue that allows for significant stretching as the bladder fills with urine. Transitional epithelium is unique because it can change shape and number of cell layers based on the bladder's fullness. When the bladder is empty, the cells appear more cuboidal and the epithelium appears thicker, while when the bladder is full, the cells flatten and the epithelium becomes thinner. This adaptability is critical for accommodating varying volumes of urine and protecting the underlying tissues from the potentially harmful effects of urine.

The other types of epithelial tissues mentioned lack this capability; simple squamous epithelium is thin and best for diffusion and filtration, cuboidal epithelium provides secretion and absorption but does not have the ability to stretch significantly, and pseudostratified columnar epithelium, which is primarily involved in secretion and movement of mucus, does not accommodate stretching either. Thus, transitional epithelium is uniquely suited to the specific functional demands of the urinary bladder.