The Vagus Nerve

Lesson objective:

In this lesson, we identify the vagus nerve as one of the nerves in the gastrointestinal tract. We also cover its essential role in the process of communicating between the brain and the body

In the last video we discussed two sides of the autonomic nervous system–the sympathetic and parasympathetic. There is one other key element of the autonomic nervous system that deserves our focus here, and that is the vagus nerve.

The vagus nerve is the tenth cranial nerve (there are 12 total), meaning it is one of the nerves that rises directly from the brain, and in this case the brain stem. 

It is an important component of the parasympathetic nervous system, and runs from the brain all the way down the spine, branching out to various organs including some skeletal muscles. 

It is the longest nerve in the autonomic nervous system and has the widest distribution in the body.

The vagus nerve connects the brainstem with core bodily functions including digestion, heart function, and breath. It helps regulate and control these responses—how you breathe, how your blood pumps, and how your gut processes food.

It is like a superhighway of communication and information signals from the brain directly to bodily processes.

The vagus nerve has a direct relationship with the “brakes” function of the parasympathetic nervous system. It stimulates many resting functions, which are often the opposite of the functions activated by the sympathetic nervous system. 

As said, the sympathetic nervous system is generally activated by stressful situations. 

The sympathetic nervous system controls many of the functions that are needed to confront stress, including increased blood pressure, dilated pupils, and opening of airways in the lungs.

Thus, given its relationship with the parasympathetic nervous system, the vagus nerve is an important component of relaxation exercises, exercises that deliberately stimulate resting functions in the body. 

We’ll be returning to the vagus nerve over and over again as we explore in greater detail how stress and trauma affect the body and brain, including the nervous system.