Anatomy
Summary
The vagus nerve, or cranial nerve X, is the longest cranial nerve, originating in the medulla and exiting the cranium via the jugular foramen along with cranial nerves IX and XI, and eventually reaching the thorax and abdomen. The vagus nerve has a broad range of functions. It extensively innervates the larynx, including muscles involved in producing sound and speech. In addition, it innervates muscles of the pharynx and soft palate, including the levator veli palatini, which elevates the soft palate during swallowing. The vagus nerve also contributes to the gag reflex, specifically the efferent limb.
The vagus nerve conveys sensory information from the larynx and the lower part of the pharynx and mediates the cough reflex. And it carries somatic sensation from the external auditory canal and a small part of the auricle just external to the canal. The vagus nerve also transmits visceral sensory information from the thorax and abdomen. This visceral sensory information includes chemoreceptors and baroreceptors at the aortic arch. Finally, the vagus nerve provides parasympathetic innervation to thoracoabdominal viscera including the heart and gut.
Lesson Outline
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FAQs
The vagus nerve, or CN X, has motor, sensory, and parasympathetic components. These include innervation of the larynx, pharynx, and soft palate, and parasympathetic innervation of thoracoabdominal viscera including the heart, lungs, and digestive tract. The vagus nerve is also involved in the gag reflex and the cough reflex.
The vagus nerve (CN X) originates in the medulla and exits the cranium via the jugular foramen along with cranial nerves IX (glossopharyngeal) and XI (accessory).
The vagus nerve supplies motor innervation to the levator veli palatini muscle. This muscle elevates the soft palate during swallowing and helps close off the nasopharynx, preventing food from entering the nasal cavity.
The gag reflex is mediated by both the glossopharyngeal nerve (cranial nerve IX) and the vagus nerve (cranial nerve X). The glossopharyngeal nerve provides the afferent limb while the vagus nerve supplies the efferent limb.
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