Other fibers from lateral grey column neurons pass through the sympathetic trunk without synapsing there. The greater splanchnic nerve leaves the vertebral levels T5-T9 and synapses in the abdomen in the celiac ganglia, which innervates the celiac artery (splanchnic nerves are the nerves that innervate thoracic and abdominal viscera). The lesser splanchnic nerve travels from the vertebral levels T10-T11 to the abdomen’s superior mesenteric ganglia, which innervates the superior mesenteric artery, and to the aorticorenal ganglion. The least, or lowest, splanchnic nerve connects the T12 level to the renal plexus. The lumbar splanchnic nerves from the upper two lumbar segments synapse in the abdomen on the inferior mesenteric ganglia, associated with the inferior mesenteric artery. In addition, some thoracic fibers in the splanchnic nerves innervate the adrenal medulla, a ganglion in the abdomen that mediates the sympathetic response to stress.