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The dorsal nucleus of vagus nerve (or posterior nucleus of vagus nerve or dorsal vagal nucleus or nucleus dorsalis nervi vagi or nucleus posterior nervi vagi) [1] is a cranial nerve nucleus of the vagus nerve (CN X) situated in the medulla oblongata of the brainstem ventral to the floor of the fourth ventricle.
These nerves release acetylcholine to stimulate two end effects. One, the parietal cells in the body of the stomach are stimulated to release H +. Two, the ECL cells of the lamina propria of the body of the stomach are stimulated to release histamine. Vagal stimulation of the peptidergic neurons, occurring simultaneously, leads to the release ...
They argue that polyvagal theory incorrectly portrays the role of the different vagal nuclei in mediating the freeze response. According to their analysis, the evidence "does not support a role of the 'dorsal vagal complex' in freezing as proposed by the PVT" and the dorsal vagal complex "should not be linked to passive defensive behavior".
The vagus nerve is also responsible for regulating inflammation in the body, via the inflammatory reflex. [7] Efferent vagus nerve fibers innervating the pharynx and back of the throat are responsible for the gag reflex. In addition, 5-HT 3 receptor-mediated afferent vagus stimulation in the gut due to gastroenteritis is a cause of vomiting. [8]
In most cases, vagal tone is not measured directly. Instead the processes affected by the vagus nerve – specifically heart rate and heart rate variability – are measured and used as a surrogate for vagal tone. Increased vagal tone (and thus vagal action) is generally associated with a lower heart rate and increased heart rate variability.
The area postrema makes up part of the dorsal vagal complex, which is the critical termination site of vagal afferent nerve fibers, along with the dorsal motor nucleus of the vagus and the NTS. Nausea is most likely induced via stimulation of the area postrema via its connection to the NTS, which may serve as the beginning of the pathway ...
Fibers cross over to and join the vagus nerve in the jugular foramen. [8]: 86–88 Sensory cell bodies are located in the inferior jugular ganglion, [9] and the fibers terminate in the solitary nucleus. [8]: 86–88 Parasympathetic fibers to segments of the trachea and esophagus in the neck originate in the dorsal nucleus of the vagus nerve. [9]
In the abdomen, general visceral afferent fibers usually accompany sympathetic efferent fibers. This means that a signal traveling in an afferent fiber will begin at sensory receptors in the afferent fiber's target organ, travel up to the ganglion where the sympathetic efferent fiber synapses, continue back along a splanchnic nerve from the ganglion into the sympathetic trunk, move into a ...