Vagus nerves


The visceral organs of the abdominal and thoracic cavity receive their innervation from the motor and sensory fibers of the vagus nerves.


The beginning of the motor fibers can be traced to the nucleus ambiguus as well as the dorsal mototr nucleus of the vagus, which can be found in the medulla oblongata. From here, it traverses its way through the jugular foramen.

The vagus nerve has numerous branches which innervate various organs, which is obvious considering it is the longest of the cranial nerves.

Muscles of the lungs, heart, larynx, pharynx, esophagus, respiratory tract, and abdominal viscera (except the lower portion of the intestines) all benefit from the vagus nerve.


Vagus nerves
Image: Vagus Nerves
Speech is permitted through a branch of the vagus nerve, the laryngeal nerve, which innervates the larynx. The sensory fibers follow a nearly identical path in relation to the motor fibers, thus innervating the same organs in nearly the same manner. The sensory fibers are responsible for relaying information to the brain which can alter behavior such as hunger, intestinal discomfort, distention, and laryngeal motion and movement.

The muscles which are innervated by the motor fibers of the vagus nerve yield proprioceptors that give way to sensory fibers. If one of the vagus nerves is damaged, there would likely be great difficulty swallowing, impairment of the ability to vocalize, or some visceral disturbances. Significant damage to both vagus nerves would result in death, as there are too many visceral organs that rely on this nerve for basic motor functions.
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