Define micturition.

The process of eliminating urine from the urinary bladder is called micturition. As the urine accumulates, the muscular walls of the bladder expand. The walls stimulate the sensory nerves in the bladder, setting up a reflex action. This reflex stimulates the urge to pass out urine. In discharge urine, the urethral sphincter relaxes, and the smooth muscles of the bladder contract; this forces the urine out of the bladder.