[The mucosal zones of the female urethra].

The short female urethra contains mucosal zones varying in extent. The proximal part, starting at the urinary bladder, is lined by a typical urothelium. It consists of several cell layers, which are covered by particularly large cells. After only a few millimeters this urothelium gives way to a stratified non-keratinized squamous epithelium containing abundant deposits of glycogen. Within this epithelium, islets varying in the extent of a stratified columnar epithelium they occupy are found. The squamous epithelium lines almost the whole length of the urethra up to its distal segment, changing shortly before the orificium externum urethrae to a stratified non-keratinized squamous epithelium which continues into the epithelium of the labia minora. This arrangement of the mucosal zones has been found in autopsy material from young women (25 and 29 years). In middle-aged women (41 and 43 years) the stratified non-keratinized squamous epithelium still predominates. In old women (84 and 90 years) only remnants of the stratified non-keratinized squamous epithelium are recognizable. Columnar epithelium lines the total length of the urethra. These results indicate that the structure of the female urethra depends on age and presumably also on the hormonal state of the mucosal zones.