Explain micturition

The Urinary bladder collects the urine formed by the nephron and it stores the urine till a voluntary signal is given by the central nervous system. As the wall of the urinary bladder is stretched by the increase in the volume of the collected urine the signal is passed to the CNS. The CNS in return passes on motor messages to start the contraction of the smooth muscles of the bladder and simultaneously there is relaxation of the urethral sphincter which causes the release of urine. This process involved in the release of urine is called micturition.