Transitional epithelium is a type of stratified epithelium tissue consisting of multiple layers of epithelial cells which can contract and expand as needed. It is so named because of this function in the transition of degree of distension. It has a basement membrane. This tissue structure type is found in urothelium, including that of the renal pelvis, urinary bladder, the ureters, the superior urethra, and the prostatic and ejaculatory ducts of the prostate.