THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The hollow portion of the urinary bladder is known as the lumen, and it needs to expand as the bladder fills with urine and contract when a person empties their bladder. Transitional epithelial tissue can expand and stretch, which allows the urinary bladder to expand as it is filled with urine.

Detailed explanation-2: -Urothelium or transitional epithelium. This is the layer of cells that lines the inside of the kidneys, ureters, bladder, and urethra. Cells in this layer are called urothelial cells or transitional cells.

Detailed explanation-3: -Transitional epithelium: A transitional epithelium (also known as urothelium) is made up of several layers of cells that become flattened when stretched. It lines most of your urinary tract and allows your bladder to expand.