22/02/2021
The vagus nerve is the tenth cranial nerve and interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It is the longest nerve of the autonomic nervous system in the human body.
The vagus nerve supplies motor parasympathetic fibers to all the organs (except the adrenal glands), from the neck down to the second segment of the transverse colon. The vagus also controls a few skeletal muscles.
The vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech (via the recurrent laryngeal nerve). It also has some afferent fibers that innervate the inner (canal) portion of the outer ear and part of the meninges.
Efferent vagus nerve fibers innervating the pharynx and back of the throat are responsible for the gag reflex. Stimulation of the vagus nerve in the cervix uteri (as in some medical procedures) can lead to a vasovagal response.
