Apparatus to control physiological functions, including urinary track physiological functions are described. The apparatus includes an electrode(s) configured to be placed on or in a targeted component of a pudendal nerve and to stimulate the targeted pudendal nerve pudendal. The targeted component of the pudendal nerve includes a pudendal nerve urethral afferent, and afferent nerve fibers in the deep perineal nerve. The apparatus includes a controller coupled to the electrode to apply an electrical signal having an amplitude and a selected frequency chosen to stimulate the targeted component. The controller operates in a first mode to apply a first frequency without substantially changing the amplitude for achieving a first physiologic response and the controller operates in a second mode to apply a second frequency, different than the first frequency, for achieving a second physiologic response different than the first physiologic response.