The solitary tract (tractus solitarius, or fasciculus solitarius), is a compact

fiber bundle In mathematics, and particularly topology, a fiber bundle (or, in Commonwealth English: fibre bundle) is a space that is a product space, but may have a different topological structure. Specifically, the similarity between a space E and a p ...

that extends longitudinally through the posterolateral region of the

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

. The solitary tract is surrounded by the

solitary nucleus In the human brainstem, the solitary nucleus, also called nucleus of the solitary tract, nucleus solitarius, and nucleus tractus solitarii, (SN or NTS) is a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column ...

, and descends to the upper cervical segments of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

. It was first named by Theodor Meynert in 1872.

Composition

The solitary tract is made up of primary sensory fibers and descending fibers of the vagus,

glossopharyngeal The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to t ...

, and facial nerves.

Function

The solitary tract conveys afferent information from stretch receptors and

chemoreceptors A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...

in the walls of the cardiovascular, respiratory, and intestinal tracts. Afferent fibers from cranial nerves 7, 9 and 10 convey taste ( SVA) in its rostral portion, and general visceral sense ( general visceral afferent fibers, GVA) in its caudal part.

Taste bud Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...

s in the mucosa of the tongue can also generate impulses in the

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...

regions of the solitary tract. The efferent fibers are distributed to the solitary tract nucleus.

Synonyms

There are numerous synonyms for the solitary tract: *round fasciculus (Latin: fasciculus rotundus) *solitary fasciculus (Latin: fasciculus solitarius) *solitary bundle (Latin: funiculus solitarius) *Gierke respiratory bundle (Named for German anatomist Hans Paul Bernhard Gierke).Stedman's Medical Eponyms
by Thomas Lathrop Stedman; Lippincott Williams & Wilkins, 2005 - Medical - 899 pages *Krause respiratory bundle (Named for German anatomist Johann Friedrich Wilhelm Krause).

References

* {{Authority control Medulla oblongata Neurophysiology Vagus nerve Glossopharyngeal nerve Facial nerve Gustatory system Human homeostasis Innervation of the tongue