The role of the vagus nerve in the nervous system (2023)

this onevagus nerveAlso known as the tenth cranial nerve or the X cranial nerve, it is a long nerve that originates from thebrain stemAnd it extends through the neck to the chest and abdomen. Its task is to regulate vital bodily functions such as heart rate, blood pressure, breathing and digestion.

This article discusses the anatomy and function of the vagus nerve and medical conditions that can affect the vagus nerve. It also investigates the effectiveness of vagus nerve stimulation and where the procedure might be useful.

The role of the vagus nerve in the nervous system (1)

What is the vagus nerve?

The vagus nerve is the longest nerveautonomic nervous systemControls involuntary bodily functions.

The autonomic nervous system consists of the parasympathetic nervous system, which controls the "rest and digest" function, and the parasympathetic nervous system, which controls the "rest and digest" function.sympathetic nervous system, which governs the fight-or-flight response. These two parts are often considered to be in opposition to each other. The vagus nerve is the main nerve of the parasympathetic nervous system.


The vagus nerve transmits motor and sensory information to various organ systems in the body, including:

  • Cardiovascular system, including the heart and major blood vessels
  • respiratory system, including the lungs and airways
  • digestive system, including the throat, esophagus, stomach and intestines

motor function

The vagus nerve carries nerve signals to the brain to regulate involuntary functions such as heart rate, breathing, and blood pressure.writhing(wave-like contraction of the muscles that move food through the digestive tract).

sensory function

The vagus nerve also provides sensory information to the skin and muscles, thereby stimulatingreflex actionExamples include coughing, sneezing, swallowing, gagging, and vomiting. Sensory information also stimulates bodily functions such as sweating, salivation, mucus production, and the urge to urinate.

The vagus nerve and the gut-brain axis

The vagus nerve also forms a connection between the gut and the brain, called the vagus.brain-gut axis. In recent years, scientists have discovered a link between dysfunction of the brain-digestive axis and diseases such as obesity, epilepsy and depression.


The vagus nerve is one of the 12 nervescranial nerve. Although there are actually two vagus nerves (left and right), they are collectively called the "vagus nerve".It has motor fibers and sensory fibers.

The vagus nerve is the longest and most complex cranial nerve. Its subsidiaries include:

  • Pharynx and laryngeal branchesIt transmits motor impulses to the pharynx and larynx
  • heart branchslow heartbeat
  • pulmonary branchsqueeze the bronchi
  • A branch of the esophagusControls the involuntary muscles of the esophagus, stomach, gall bladder, pancreas and small intestine; and stimulates the bowels and gastrointestinal secretions.

Anatomy of the trachea

The role of the vagus nerve in the nervous system (2)

a common problem

Dysfunction of the vagus nerve disrupts many of its involuntary body functions, which are called autonomic dysfunction orautonomic dysfunction.

Problems with the vagus nerve (called vagus neuropathy) can cause different symptoms, depending on which part of the nerve is affected.

Conditions associated with vagus neuropathy include:

heart beat problems

arrhythmia: This is an arrhythmia. may also includeBradycardia(abnormally slow heartbeat),tachycardia(abnormally fast heartbeats) and palpitations (skipping of the heart).

nerve damage

There are many conditions that can damage the vagus nerve, including alcoholism, diabetes, benign or cancerous tumors, and physical trauma.On the other hand, there are many diseases caused or affected by vagal dysfunction, the root cause of which may not be known.


Gastropareza is a digestive disorder in which food does not move properly from the stomach to the intestines, causing abdominal pain and bloating.

Gastroparesis can also get worseacid reflux, when stomach acid refluxes intoesophagus(feeding tube). This includes a chronic form of acid reflux calledGastroesophageal reflux disease (GERD).

they will be syncopated

they will be syncopatedFainting caused by a sudden strong emotional reaction, such as fear or the sight of blood. Other symptoms include tinnitus, narrowed vision and nausea.

hard to swallow

hard to swallowDifficulty swallowing food or liquids.

throat disease

this is dysfunctionthroat(voice box) can cause hoarseness and speech problems.

orthostatic hypotension

orthostatic hypotensionDizziness or fainting caused by a sudden drop in blood pressure when standing or standing up.


hiccupsAnother name for hiccups.

vagus nerve test

Diagnosing vagus nerve dysfunction can be difficult because damage can occur anywhere along the length and branches of the nerve.

A simple but effective way to test the vagus nerve is by examination gag reflex. This involves scratching the back of the throat with a soft cotton ball. If the patient does not convulse, this may indicate a problem with the brainstem where the vagus nerve originates.

Additional tests may be needed to check for possible injury or worsening or damage to the vagus nerve:

  • Doppler ultrasound: This non-invasive imaging tool uses sound waves to detect thinning of the vagus nerve in the neck. It also checks for abnormalities in the blood vessel that supplies the vagus nerve in the neck.
  • Valsalvin manevar: This is a test that requires you to exhale forcefully while keeping your nose and mouth closed. It is used to watch how your heart responds to changes in pressure and can detect abnormalities that point to autonomic dysfunction.
  • skin conductance reaction: This uses a device that detects if a person is sweating under stress. oneelectrocardiogram (ECG)It can be used at the same time to see if your heart rate changes.

Additional tests may be ordered to describe your symptoms or narrow down possible causes.

stimulation of the vagus nerve

stimulation of the vagus nerve) (VNS) is a medical treatment in which electrical impulses are sent to the vagus nerve for treatmentepilepsyormajor depressive disorder (MDD).

Both epilepsy and major depressive disorder are thought to result from dysfunction of the brain-digestive axis, in which the vagus nerve plays a central role. Dysfunction of the brain-gut axis can lead to microbial overgrowth in the digestive tract, directly interfere with brain function, and increase the risk of epilepsy and depression.

VNS is a device attached to the chest that sends gentle electrical impulses that "resynchronize" the nerve signals between the brain and gut to function more normally.

In the US, VNS is approved as adjunctive therapy for drug-resistant patients 4 years of age and olderfocal seizures.

How effective is VNS?

Studies have shown that VNS treatment reduces the frequency of seizures by 51% after one year. Although the effectiveness of vagus nerve stimulation (VNS) in the treatment of depression is difficult to establish, current evidence suggests that it is well tolerated and may be beneficial, but further research is needed.

VNS is being investigated for other conditions affected by autonomic dysfunction, includingobesity,hypertension(hypertension),anxiety,cardiac arrest, arrhythmia,Alzheimer's disease, iParkinson's disease.

Current research

For those who do not have access to a VNS device or who want a more natural approach to treatment, there are practices that can help manage autonomic dysfunction.

Research shows that certain home remedies can help stimulate the vagus nerve by slowing the heart rate and reducing emotional stress that can cause or worsen vagal disorders.

Examples include:

  • deep breathing exercises: Slow, conscious breathing is thought to stimulate the vagus nerve, which not only increases heart rate and blood pressure, but also improves digestion.
  • mindfulness practice: This includes practices likeyogaiTai ChiIn which breathing is synchronized with body movement. Some research suggests that the practice improves vagal tone, which slows the heart and lowers blood pressure.
  • foot reflexology: This massage-based practice has been shown to slow heart rate and breathing, lower blood pressure and increase oxygen saturation, suggesting it actively stimulates the vagus nerve.
  • music therapy: Certain types of music are believed to positively affect mood and induce beneficial autonomic responses. This is especially true for low-frequency sounds delivered with slow, rhythmically structured music.
  • soak in cold water: Immersing the face in cold water is thought to indirectly stimulate the vagus nerve. It turns out that after the initial cold shock, the heart rate starts to slow down. Swimming in open water can have the same effect.

It is not clear whether these techniques stimulate the vagus nerve directly like electrical VMS, but each technique is known to induce positive physiological responses that can help relieve stress and improve mood.


The vagus nerve is the longest and most complex cranial nerve. It has motor and sensory fibers distributed throughout the body, influencing many important processes. It also connects the brain to the gastrointestinal tract.

There are tests that can help determine how well the vagus nerve is working, and there are procedures (such as vagus nerve stimulation) that can help treat neurological disorders such as epilepsy and depression.


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