part_of starts_at ends_at urinary system urogenital sinus bladder-urethra transition zone bladder-urethra junction anatomical_structure The bladder-urethra transition zone (syn: bladder-urethra junction) (TS:22-TS:28) is comprised of epithelium and mesenchyme of bladder-urethra transition zone. The zone or region located where the bladder neck meets the urethra/pelvic urethra, marking the junction where these two different epithelia meet (urothelium of bladder and epithelium of pelvic urethra). It is similar to transitional zones in other organs, such as the female cervix and the Z-line in the oesophagus. It is located close to where the nephric duct attaches to the urogenital sinus. Part of the urogenital sinus (to TS:26) and part of the urinary system. Use these terms to annotate expression in the epithelium or mesenchyme where the bladder meets the pelvic urethra, when the tissue cannot be identified as being either part of the bladder or part of the pelvic urethra. EMAPA:36332 lower urinary tract TS22 TS28