Where can transitional epithelium be found?

• A. Cornea
• B. Skin
• C. Bladder
• D. Conjunctiva

Answer: (C)

Transitional epithelium is a stretchable, multi-layered lining that can accommodate changes in organ volume without tearing. In the urinary system, especially the bladder, the epithelium must expand as urine fills the bladder and contract as it empties. It achieves this with surface umbrella cells that can flatten as the bladder distends, maintaining a watertight barrier. Tight junctions and a specialized apical membrane coat help preserve impermeability during stretch. This tissue type is characteristic of the urinary tract, including the bladder, renal pelvis, and part of the ureters. Other structures listed are lined by different epithelia: the cornea has a non-keratinized but non-stretching surface epithelium; the skin is keratinized; the conjunctiva is a non-keratinizing mucous membrane epithelium. Therefore, the bladder is the typical location for transitional epithelium.