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Figure 1. Sympathetic input to the gastrointestinal tract is conveyed by postganglionic efferent neurons that arise from the celiac, superior mesenteric, and inferior mesenteric ganglia. Sympathetic fibers projecting to the stomach, duodenum, and small intestine originate from spinal segments T6-T9, whereas those innervating the colon derive from segments L2-L5. Parasympathetic innervation is provided by the vagus nerve and pelvic splanchnic nerves. The cell bodies of vagal sensory neurons are located in the nodose ganglion. In contrast, general visceral afferent fibers, including those associated with sympathetic and pelvic splanchnic pathways, travel alongside their corresponding efferent nerves, and their neuronal cell bodies are found in the dorsal root ganglia. Image created with Adobe Illustrator.