Vagus (X) Nerve

Vagus (X) Nerve

The longest mixed cranial nerve serves as the primary highway for the parasympathetic nervous system, distributed from the head and neck into the thorax and abdomen.

Vagus (X) Nerve: Location

In the neck, the vagus nerve runs vertically in the carotid sheath, positioned between the internal jugular vein and the carotid artery.

Vagus (X) Nerve: Pathway

Sensory axons in the vagus nerve arise from the skin of the external ear

Vagus Nerve (X): Sensory Function

The vagus nerve carries sensory information from the external ear, epiglottis, pharynx, neck and throat muscles, carotid and aortic bodies, and most organs in the thoracic and abdominal cavities.

Vagus Nerve (X): External Ear

Sensory axons of the vagus nerve carry touch, pain, and temperature sensations from the skin of the external ear.

Vagus Nerve (X): Taste

Sensory axons of the vagus nerve carry taste information from a small number of taste buds in the epiglottis and pharynx.

Vagus Nerve (X): Proprioception

The vagus nerve carries proprioceptive information from muscles of the neck and throat.

Vagus Nerve (X): Baroreceptors and Chemoreceptors

The vagus nerve carries information from baroreceptors in the carotid sinus, which monitor blood pressure, and from chemoreceptors in the carotid and aortic bodies, which monitor blood oxygen and carbon dioxide levels.

Vagus Nerve (X): Visceral Sensory Input

Most sensory fibers of the vagus nerve arise from visceral sensory receptors in organs of the thoracic and abdominal cavities to convey sensations such as hunger, fullness, and discomfort

Vagus Nerve (X): Sensory Ganglia

The cell bodies of vagal sensory neurons are located in the superior and inferior ganglia, which pass through the jugular foramen to end in the medulla and pons

Vagus Nerve (X): Motor Function

The branchial motor neurons of the vagus nerve arise from nuclei in the medulla oblongata that supplies the pharynx, larynx, and soft palate for swallowing, vocalization, and coughing.

Vagus Nerve (X): Autonomic Output

Parasympathetic motor neurons originate in nuclei of the medulla and supply the lungs, heart, digestive glands, and smooth muscle of the respiratory passageways, esophagus, stomach, gallbladder, small intestine, and most of the large intestine

Vagus Nerve (X): Parasympathetic Output

Parasympathetic motor neurons stimulate digestive smooth muscle contractions and glandular secretion, constrict respiratory passageways, and decrease heart rate.