Which part of the duodenum receives sympathetic innervation from the greater splanchnic nerve?

The upper half of the second part of the duodenum receives sympathetic innervation from the greater splanchnic nerve, which arises from the thoracic spinal nerves T5 to T9. This nerve carries sympathetic fibers that play a crucial role in the autonomic nervous system, particularly in the regulation of digestive processes.

The greater splanchnic nerve specifically targets the foregut, which encompasses structures stemming from the celiac trunk, including parts of the duodenum. It's during this innervation that signals are sent to modulate functions such as increased blood flow to the digestive organs, coordination of digestive secretions, and influencing motility. In contrast, other segments of the duodenum, such as the lower halves of the first and second parts, may have different sources of sympathetic innervation, typically through the lesser splanchnic nerve or other pathways that do not overlap with the greater splanchnic nerve. This distinction helps clarify the specific roles and targets of sympathetic fibers within the gastrointestinal tract.