Vagus Nerve: What It Is And What Functions It Has In The Nervous System
The vagus nerve is number 10 of the cranial nerves Among other things, it is responsible for transmitting information related to sensory and muscular activity, as well as anatomical functions.
Next we will briefly see what the cranial nerves are, and later we will define the vagus nerve.
The lower part of our brain is made up of a complex network of nerves that we know as “cranial nerves” or “cranial nerves.” In total there are 12, They originate directly in our brain and they are distributed along different fibers through holes at the base of the skull towards the neck, thorax and abdomen.
Each of these nerves is made up of fibers that fulfill different functions and that arise from a specific part of the brain (it can be at the base or the stem). Depending on their location and the specific place they depart from, The cranial nerves are divided into subgroups:
At the same time, Each of them has different names depending on their origin, their activity, or the specific function that they comply. In the following sections we will see how the vagus nerve is defined and what functions it has.
What is the vagus nerve?
The vagus nerve is one of the cranial nerves that is distinguished by having four nuclei and five different fiber types. Specifically, it is cranial nerve number the most predominant neural effector of the parasympathetic nervous system since it comprises 75% of all its nerve fibers (Czura & Tracey, 2007).
It is known as the “vagus” nerve to refer to ramblings and detours. It is the nerve whose course is the longest of the cranial nerves, they extend and distribute widely below the level of the head.
It arises in the medulla oblongata or medulla oblongata, and advances towards the jugular foramen passing between the glossopharyngeal and spinal accessory nerves, and is composed of two ganglia: one superior and one inferior.
Starting from the medulla oblongata and through the jugular foramen, the vagus nerve descends towards the thorax, crossing different nerves, veins and arteries. Both its left and right parts extend inside the neck to the thorax; For this reason, it is responsible for carrying part of the parasympathetic fibers to the thoracic viscera.
The vagus nerve interacts especially with the immune system and the central nervous system and performs motor functions in the larynx, diaphragm, stomach, heart It also has sensory functions in the ears, tongue and visceral organs such as the liver.
Damage to this nerve can cause dysphagia (problems swallowing), or incomplete closure of the oropharynx and nasopharynx. On the other hand, Pharmacological interventions on the vagus nerve can help control different pain for example those caused by cancer and tumors of the larynx or intrathoracic diseases.
Connection with other nerves
As we saw before, the vagus nerve connects with different nerves, that is, it exchanges several of its fibers and functions. According to Barral, JP. & Croibier, A. (2009), The nerves with which it connects are the following:
Nerve fibers, or nerves, are the extensions that connect the center of each nerve cell to the next. They transmit signals known as action potentials and they allow us to process stimuli.
The latter are not the only types of fibers, there are also those to connect and activate effector organs, muscle fibers or glands. According to Rea (2014), the vagus nerve has the following types of fibers.
1. Brachial motor fiber
Activate and regulate the muscles of the pharynx and larynx
2. Sensory visceral fiber
Responsible for transmitting information from a wide variety of organs such as the heart and lungs, the pharynx and larynx, and the upper part of the gastrointestinal tract.
3. Visceral motor fiber
It is responsible for carrying the parasympathetic fibers from smooth muscle to the respiratory tract, heart and gastrointestinal tract
4. Special sensory fiber
The vagus nerve transmits information necessary for taste to the palate and epiglottis (the fibrous cartilage that closes the entrance to the larynx during swallowing)
5. General sensory fiber
This component allows the passage of information from parts of the ear and dura mater into the posterior cranial fossa.
