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General Practice 2023

Vagus nerve: what é, anatomy and main functionsções

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Vagus nerve: what é, anatomy and main functionsções
Vagus nerve: what é, anatomy and main functionsções

The vagus nerve, also known as pneumogastric nerve, is a nerve that travels from the brain to the abdomen, and along its path, gives rise to several branches that innervate various cervical, thoracic and abdominal organs, with functions sensory and motor, being important for the maintenance of vital functions such as regulation of heart rate and blood, for example.

The pair of vagus nerves, located on each side of the body, is the 10th pair of a total of 12 cranial pairs that connect the brain to the body. As the cranial nerves are named as Roman numerals, the vagus nerve is also called the X pair, and is considered the longest of the cranial nerves.

Certain stimuli to the vagus nerve, caused by anxiety, fear, pain, temperature changes or simply by standing for a long time, can cause the so-called vasovagal syncope, in which the person may experience intense dizziness or fainting., as this nerve can cause a drop in heart rate and blood pressure.Understand what vasovagal syncope is and how to treat it.

Anatomy of the vagus nerve

cranial pairs

Origin of the vagus nerve

The vagus nerve is the largest cranial nerve and originates at the back of the medulla oblongata, a brain structure that connects the brain with the spinal cord, and exits the skull through an opening called the jugular foramen, descending through the neck and chest until it ends in the stomach.

During the course of the vagus nerve, it innervates the pharynx, larynx, heart and other organs, and it is through it that the brain perceives how these organs are doing and regulates several of their functions.

Main functions

Some of the main functions of the vagus nerve include:

  • Cough, swallowing and vomiting reflexes;
  • Vocal cord contraction for voice production;
  • Control of heart contraction;
  • Decreased heart rate;
  • Respiratory movements and constriction of the bronchi;
  • Coordination of esophageal and bowel movements, and increased gastric secretion;
  • Sweat production.

In addition, the vagus nerve shares some of its functions with the glossopharyngeal nerve (IX pair), especially in the neck region, being responsible for the gustatory sensation, where the vagus nerve is more related to sour and glossopharyngeal with the bitter taste.

Alterations of the vagus nerve

A vagus nerve palsy can cause difficulty swallowing, hoarseness, difficulty speaking, contractions in the muscles of the pharynx and larynx, and changes in blood pressure and heart rate. This paralysis can occur due to trauma, injuries in surgery, compression by tumors or certain neurological syndromes.

In addition, there are situations that cause excessive stimulation of the vagus nerve, generating a situation called vagal syncope or fainting. It usually occurs in young individuals and is due to a reduction in heart rate and blood pressure, due to lack of oxygen in the brain, causing fainting. Here's what to do if you faint.

Vaginal syncope can be caused by:

  • Exposure to heat;
  • Strong emotions such as anger;
  • Standing for a long time;
  • Temperature changes;
  • Swallowing very large foods;
  • Being at a high altitude;
  • Feeling hunger, pain, or other unpleasant experiences.

Stimulation of the vagus nerve can also be done through a massage in the lateral region of the neck. Sometimes the vagal maneuver is performed by doctors in an emergency to regularize the cardiac arrhythmia.

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