Editing Urination (section)

=====Denervation=====
When the afferent and efferent nerves are both destroyed, as they may be by tumors of the [[cauda equina]] or [[filum terminale]], the bladder is flaccid and distended for a while. Gradually, however, the muscle of the "decentralized bladder" becomes active, with many contraction waves that expel dribbles of urine out of the urethra. The bladder becomes shrunken and the bladder wall hypertrophied. The reason for the difference between the small, hypertrophic bladder seen in this condition and the distended, hypotonic bladder seen when only the afferent nerves are interrupted is not known. The hyperactive state in the former condition suggests the development of denervation hypersensitization even though the neurons interrupted are [[preganglionic]] rather than [[postganglionic]].