The outline of principal events of urination is given below in unordered manner: (1) Stretch receptors on the wall of urinary bladder send signal to the CNS (2) The bladder fills with urine and becomes distended (3) Micturition (urination) (4) CNS passes on motor messages to initiate the contraction of smooth muscles of bladder and simultaneous relaxation of urethral sphincter The correct order of steps for urination is