Final answer:
Transitional epithelium is the type of epithelial tissue lining the bladder, characterized by its ability to change shape as the bladder fills and empties. These cells transition from a thicker, folded lining in an empty bladder to a thinner, unfolded lining in a full bladder. They are unique to the urinary system and facilitate the bladder's storage and expulsion of urine.
Step-by-step explanation:
The type of epithelial tissue lining the bladder is known as transitional epithelium. This tissue is specially adapted to fluctuate in response to the distention of the bladder. In an empty bladder, the cells of the transitional epithelium are piled up and the epithelial lining is folded. This gives the appearance of multiple layers. As the bladder fills with urine, the epithelial lining unfolds and the individual cells transition from a cuboidal shape to a squamous shape, causing the lining to become thinner. Thus, the overall tissue transitions from thick to thin.
Transitional epithelia, also referred to as uroepithelial cells, appear only in the urinary system, such as the ureters and bladder. These cells have the unique ability to slide over each other, allowing the bladder to expand and contract. This elasticity supports the bladder's function in storing and expelling urine.
An easy way to remember the function of transitional epithelia is by thinking about how the bladder itself operates: as it fills, it expands similar to a balloon, and as it empties, it contracts. Transitional epithelia have the structural flexibility to accommodate this change in volume without being damaged.