Vagus nerve or cranial nerve X
Description:
The vagus nerve is a mixed cranial nerve that is distributed from the head and neck into the thorax and abdomen as it follows the path of the gut tube (digestive and respiratory systems). In the neck, it lies medial and posterior to the internal jugular vein and common carotid artery. Sensory axons in the vagus nerve arise from the skin of the external ear, taste buds in the epiglottis and pharynx, and proprioceptors in the muscles of the neck and throat. Also, sensory axons come from baroreceptors (stretch receptors) in the carotid sinus, chemoreceptors in the carotid body, and sensory receptors in the respiratory and digestive passageways. These axons form nerves that join the main vagus trunk and enter the skull through the jugular foramen. They end in the medulla oblongata and pons in various nuclei.
The somatic motor neurons in the nerve arise from nuclei in the medulla oblongata and supply muscles of the pharynx, larynx, and soft palate that are used in swallowing and vocalization.
Axons of parasympathetic motor neurons in the vagus originate in the medulla and smooth muscle and glandular tissue in the respiratory and digestive passageways. They also terminate in the heart.
