Parasympathetic level for the lower ureters.

Parasympathetic level for the lower ureters.

• A. S2-4 Pelvic Splanchnic
• B. C2-Vagus
• C. T10-L2
• D. T11-L2

Answer: (A)

The main idea is that the lower ureter receives parasympathetic input from sacral outflow. Specifically, pelvic splanchnic nerves originate from S2–S4 and travel through the pelvic plexus to innervate pelvic organs, including the lower part of the ureter. This sacral parasympathetic supply promotes ureteral peristalsis and forward urine movement toward the bladder. In contrast, sympathetic fibers from higher thoracic and lumbar levels (roughly T10–L2) tend to inhibit peristalsis and contract smooth muscle, while parasympathetic input to much of the upper ureter comes from the vagus nerve, not the sacral nerves. So for the lower ureter, the parasympathetic level is S2–S4 via the pelvic splanchnic nerves.

The main idea is that the lower ureter receives parasympathetic input from sacral outflow. Specifically, pelvic splanchnic nerves originate from S2–S4 and travel through the pelvic plexus to innervate pelvic organs, including the lower part of the ureter. This sacral parasympathetic supply promotes ureteral peristalsis and forward urine movement toward the bladder. In contrast, sympathetic fibers from higher thoracic and lumbar levels (roughly T10–L2) tend to inhibit peristalsis and contract smooth muscle, while parasympathetic input to much of the upper ureter comes from the vagus nerve, not the sacral nerves. So for the lower ureter, the parasympathetic level is S2–S4 via the pelvic splanchnic nerves.