Article

Everything You Didn’t Know You Wanted To Learn About The Vagus Nerve

Published on Tuesday, March 01, 2022
by Ashlie Morrissey

Health & Wellness

AKA What Happens In Vagus, Doesn’t Stay in Vagus

Vagus nerve facts that are good to know:

10th and longest cranial nerve
Historically called the “pneumogastric nerve” because of the effects on breathing and the gut
Vagus literally means “wandering” in Latin
Called the “wandering” nerve because it starts in the brain but wanders down to the lower abdominal area, interacting with organs along the way
Controls or impacts function in almost all parts of the body from tongue to intestines and everything in between

Fun Fact: There are a total of 12 different cranial nerves, all “paired” meaning there is a right and left, and all arising from the back of the brain.

The Vagus nerve has four main functions: sensory, motor, special sensory (taste sensation near the base of the tongue), and parasympathetic. The sensory functions of the Vagus nerve are varied but include supplying sensory information for the larynx, esophagus, and most of the digestive tract. The motor functions include muscle contractions along most of the gastrointestinal tract from pharynx through most of the intestines.

The parasympathetic system is part of the body’s autonomic nervous system. The parasympathetic partners with the sympathetic nervous system to regulate bodily functions. A simple way of thinking about these systems is this: the sympathetic nervous system controls the body’s increase in functions, think “fight or flight”; the parasympathetic controls the body’s ability to relax, think “rest and digest”.

What does this mean for our gastrointestinal health particularly?

The Vagus nerve is responsible for the processing and digestion of food, also food moving normally through our gastrointestinal (GI) tract. Any damage to the Vagus nerve, or certain diseases that impair nerve function, can affect the Vagus nerve operating effectively.

These problems may show up at the beginning of the GI tract; meaning the esophagus may lose muscle tone and have difficulty pushing food down into the stomach. This can even result in food entering the lungs, causing further problems.

The Vagus nerve also affects food digestion. If it is impaired or damaged, then the body may produce too much acid in the stomach. This may lead to damage of the stomach lining, vomiting, acid reflux, and/or gastroesophageal reflux disease (GERD).

There is also the possibility of the Vagus nerve not functioning enough to release histamine- resulting in not enough acid in the stomach. Not enough acid causes symptoms also, including acid reflux, bloating, nausea, diarrhea, and nutrient deficiencies due to food not breaking down completely during the digestion.

Because the Vagus nerve helps control movement of contents through the intestines, any impairment in function also usually results in some constipation. Because of the “gut-brain axis” it is also true that emotions can contribute to irritable bowel syndrome (IBS) symptoms.

Interested in learning more about the vagus nerve? Check out my article on The Vagus Nerve and The Gut-Brain Axis which takes a closer look at the vagus nerve by touching on assessment on vagus nerve function, including how medical providers assess vagus nerve function!