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.
Review Date 5/10/2019
Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.