When the bladder fills with urine, sensory nerves send impulses to the brain indicating that the bladder is full. The sensory nerves connect with other nerves in the spinal cord to relay this information. In turn, the brain sends impulses back to the bladder instructing the bladder to empty its contents.
Update Date 8/31/2015
Updated by: Jennifer Sobol, DO, Urologist with the Michigan Institute of Urology, West Bloomfield, MI. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.