PATHOLOGY

Detailed explanation-1: -The inner lining of the urinary bladder is a mucous membrane of transitional epithelium that is continuous with that in the ureters. When the bladder is empty, the mucosa has numerous folds called rugae. The rugae and transitional epithelium allow the bladder to expand as it fills.

Detailed explanation-2: -Structure of the Bladder Wall The smooth muscle (detrusor) of the bladder wall is protected by an external serosa and on the vesical face overlain by a mucosa that itself consists of a tight transitional epithelium (urothelium), basement membrane and sub-urothelium (fig. 1A).