PPC/OMM Block 6 Practice Exam

Parasympathetic control of the bladder comes from the sacral spinal cord through the pelvic splanchnic nerves (S2–S4). These sacral parasympathetic fibers stimulate the detrusor muscle to contract and promote relaxation of the internal urethral sphincter, enabling micturition. This sacral outflow also carries afferent fibers that participate in the micturition reflex when the bladder fills. The vagus nerve (which comes from higher cervical levels) does not innervate the bladder, and thoracic/lumbar levels (T9–11 or T10–L2) provide sympathetic input that supports storage, not parasympathetic activation. So the correct parasympathetic level for the bladder is S2–S4 via the pelvic splanchnic nerves.