What is a common characteristic of transitional epithelial cells?

Transitional epithelial cells are unique in their appearance and function, which is why the correct choice highlights their shape. These cells are characterized by their ability to change shape depending on the degree of stretch in the urinary bladder and other areas where this type of epithelium is found. Typically, they tend to be round but can appear pear-shaped when stretched. This adaptability allows them to accommodate fluctuations in urine volume, which is crucial for the function of the urinary system.

The other options describe different types of epithelial cells. Flat and thin cells are typical of simple squamous epithelium, which is not applicable to transitional epithelium. Columnar cells, which tend to have a significantly larger surface area, are characteristic of columnar epithelium, primarily found in areas such as the gastrointestinal tract. Hollow and cylindrical descriptions align more closely with the structure of certain organs or tubes, but they do not accurately define the unique structure of transitional epithelial cells.