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a slender, compact fiber bundle extending longitudinally through the posterolateral region of the medulla, surrounded by the nucleus of the solitary tract, below the obex decussating over the central canal, and descending over some distance into the upper cervical segments of the spinal cord. It is composed of primary sensory fibers that enter with the vagus, glossopharyngeal, and facial nerves, and in part convey information from stretch receptors and chemoreceptors in the walls of the cardiovascular, respiratory, and intestinal tracts; in rostral parts of the tract, impulses are generated by the receptor cells of the taste buds in the mucosa of the tongue. Its fibers are distributed to the nucleus of the solitary tract.
A thin tract of visceral sensory axons from cranial nerves CN VII, CN IX, and CN X. The tract runs longitudinally, alongside the solitary nucleus in the hindbrain. Axons from the tract, which carries information from mechanoreceptors and chemoreceptors, synapse in the adjacent nucleus.
See also: tractus