What Causes the Start and Stop of Urination?

The process of urination involves a complex interaction between the brain, nerves, and muscles. Starting urination: When the bladder fills with urine, nerve signals are sent to the brain, indicating the need to urinate. The brain then sends signals back to relax the muscles of the urethra and contract the bladder muscles, allowing urine to flow out. Stopping urination: To stop urinating, the brain sends signals to contract the muscles around the urethra and relax the bladder muscles, stopping the flow of urine. According to research, there are differences in how these processes work in males and females, and they can change as people age. This coordination ensures that urination is controlled and happens at appropriate times.