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What Is a Nervus Vagus?

A diagram showing the vagus nerve.
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  • Written By: Katriena Knights
  • Edited By: A. Joseph
  • Last Modified Date: 29 September 2014
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One aspect of the study of neurology is identifying the individual nerves that work to carry sensory information from various parts of the body to the brain. The nervus vagus is an important pathway in the nervous system because it carries signals from several areas of the body, including the lungs, esophagus, stomach, larynx (voice box), pharynx, lungs, heart and a large part of the digestive system. Literally translated, "vagus" means "wandering" in Latin. The most complex as well as the longest of the nerves descending from the brain, the vagus nerve earns its name by wandering through a large area of the body to serve this wide range of organs.

A cranial nerve, the nervus vagus finds its origins in the brain, in rootlets from the lateral side of the medulla oblongata. Passing through the jugular foramen, an opening in the skull, it continues between the carotid artery and the jugular vein in the carotid sheath. From there, it spreads and branches throughout the body, giving rise to several branches along the way. Body functions that depend on the nervus vagus include peristalsis — wavelike contractions — in the gastrointestinal tract, sweating and even movement of the mouth that enables speech.

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Also known as the tenth cranial nerve or the pneumogastric nerve, the nervus vagus carries signals to these areas of the body from the brain and delivers messages back to the brain. Among other functions, this path can send signals that will lower the heart rate when necessary by interacting with the sinoatrial node. More than 80 percent of the nerve fibers in this pathway carry sensory information so the brain can interpret the overall state of the lungs, heart and viscera. The rest of the nerve fibers are motor fibers that trigger movement or action in the body. Because the nervus vagus carries both sensory and motor fibers, it is considered a mixed nerve.

Stimulation of the nervus vagus using a device similar to a heart pacemaker is sometimes used to treat epileptic seizures and some forms of depression that do not respond to medications. This pathway also can be stimulated through specific movements or muscle contractions. These types of stimulation are occasionally recommended for patients who suffer from certain kinds of heart arrhythmia. Blocking the action of the nervus vagus through similar manipulations or even cutting it in a procedure called a vogotomy is sometimes used in conjunction with bariatric surgery to treat morbid obesity.

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B707
Post 7

@BoniJ - One of your post questions was about using stimulation of the nervus vagus to help patients suffering from treatment-resistant depression.

I have read about one study relating to this. There were sixty people who had tried medication, but it wasn't effective. They were given nerve stimulation of the nervus vagus, in a single blind study. And then a period of no stimulation.

The data showed that those who were mild to moderately resistant to other treatments showed the greatest response to the nerve stimulation.

I think that much more needs to be studied in this area - but it does sound promising.

BoniJ
Post 6

It's surprising that the nervus vagus nerve controls both sensory data and movement signals. This nerve monitors the function of important organs, like the digestive system, and muscle contractions.

Apparently using something like a pacemaker can act on the nervus vagus to decrease depression in some people. I wonder how this is done and how effective it is?

One last question. I know a woman at work, who is very obese. She is researching to find a surgical method to curb her appetite. Vogotomy surgery involves blocking or cutting the nervus vagus nerve. Exactly how does this procedure help an obese person, is it dangerous, and how effective is it?

snickerish
Post 5

@Sinbad - I have read about VNS stimulation (vagus nerve stimulation) as well, and am not sold either way. One of the things I would like to know more about is how VNS stimulation is used for depression *and* to help curb food cravings.

It is neat in theory but is there science to this stimulation?

Sinbad
Post 4

The vagus nerve seems to be a part of everything!

And it is for that reason that I am a little nervous about possibly giving advice to a friend, as a friend, and definitely not as a medical professional about vagus nerve stimulation.

My friend has had depression for a long time and although she has tried different things, her depression continues to linger.

I'm sure it is controversial but I have read a few accounts of vagus nerve stimulation (vns stimulation) helping depression. Has anyone else heard of this?

Tomislav
Post 3

Another connection between the vagus nerve (commonly misspelled as the vegas nerve, which is a great way to remember the name of the nerve as the "Las Vagus Nerve") into your everyday life:

When you are using a q-tip or cotton swab, if you have ever coughed, you elicited a cough reflex which occurs when you stimulate part of the vagus nerve with your q-tip.

I have never done this, but my husband does it often. So don't be surprised the next time you cough while q-tipping!

Charmagne
Post 2

@OhDeDoh- I have worked in health care, too. These vagal attacks can result in other ways as well. I have seen or heard of vasovagal episodes resulting from standing or sitting up for too long. It can happen when someone stands up too quickly.

Things like stress, trauma, or painful stimuli can bring on attacks. Dehydration can be an agitator. Along with bowel movements, the same result can occur with urination. And as if the effects of illegal drugs weren’t bad enough, drugs like methamphetamines can cause a vagal attack.

The Nervus Vagus can be affected by so many things. It’s important to know different ways we can be harmed by things that interfere with the healthy function of this nerve.

OhDeDoh
Post 1

There are different ways the vagus nerve function can have surprising impacts on the human body. When I worked in health care with elderly patients, I learned the phrase ‘vagul out’, or ‘vaguling out’.

I know that isn’t the proper medical term. What it refers to is when a person is going to the bathroom and strains really hard. This can actually cause reduced circulation to the vagus nerve, and therefore the brain, and cause a patient to pass out.

This is actually called a vasovagal episode, or more specifically, vasovagal syncope.

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