exam 2 vagus nerve Flashcards
what type of information does the vagus nerve carry?
motor, parasympathetic, and sensory information
including some taste from the epiglottal region
what are two unique chaacteristics of the vagus nerve?
longest cranial nerve
most important parasympathetic nerve
where are the cell bodies for the motor fibers of the vagus nerve located?
in the nucleus ambiguus
where does the nucleus ambiguus receive its information from?
both cerebral hemispheres, (its a motor nuclues so from a higher level.)
where do the preganglionic parasympathetic fibers of the vagus nerve arise from?
posterior (dorsal) nucleus of the vagus
where does the posterior nucleus of the vagus receive its information from?
receives information indirectly from the hypothalamus and carotid sinus
incoming somatic sensory information carried in the vagus nerve terminates where?
spinal nucleus of C.N 5
taste and viscerosensory information carried in the vagus nerve terminates where?
nucleus of the solitary tract
what are the two peripheral ganglia associated with the vagus nerve?
superior and inferior ganglion
NOT the same as glossopharyngeal
what is the superior ganglion of the vagus nerve also known as?
the jugular ganglion
what is the inferior ganglion of the vagus nerve also known as?
the nodose ganglion
sensory information is carried in neurons whose cell bodies are located where?
superior ganglion
where does the sensory information of the vagus come from?
Dura (infratentorial/posterior fossa) auricle external auditory canal lateral tympanic membrane mucosa from the larynx and laryngopharynx viscera in the thoracic and abdominal cavities pressure receptors in the aortic arch chemoreceptors in the para-aortic body
taste from the epiglottis is carried by neurons whose cell bodies are located where?
inferior ganglion
where does taste from the epiglottis terminate?
superior part of the nucleus of the solitary tract
visceral sensory information is carried by neurons in the inferior ganglion to where?
inferior part of the solitary tract
the vagus nerve carries visceral sensory information from where?
larynx and laryngopharnx
viscera in the thoracic and abdominal cavities
pressure receptors in the aortic arch
chemoreceptors in the para-aortic body
what is the apparent origin of the vagus nerve?
emerges from lateral aspect of the medulla oblongata as a series of rootlets
when the rootlets combine and form a trunk what does the vagus nerve do before exiting the skull?
gives off a meningeal branch that supplies the dura of the posterior cranial fossa
where does the vagus nerve exit the skull?
jugular foramen
what does the meningeal branch supply?
dura of the posterior cranial fossa
how is the jugular foramne compartmentalized?
by a fibrous septum
what nerves travel anterior to the fibrous septum of the jugular foramen?
vagus nerve
accessory nerve
what nerve travels posterior to the fibrous septum of the jugular foramen?
glossopharyngeal nerve
what do the vagus and accessory nerve also share during their travels through the jugular foramen?
they share a meningeal sheath (arachnoid and dura)
where is the superior ganglion of the vagus nerve located?
jugular foramen
where is the inferior ganglion of the vagus nerve located?
just inferior to the jugular foramen (outside)
where is the auricular branch of the vagus nerve given off at?
the superior ganglion
what two structures does the auricular branch pass through on its way to the external auditory meatus?
mastoid canaliculus and the tympanomastoid fissure
what information does the auricular branch carry?
sensory information from the meatus and a small portion of the auricle
upon exiting the jugular foramen what does the vagus nerve travel inferiorly in?
the carotid sheath
while in the carotid sheath traveling inferior what two structures does it travel between?
internal carotid artery and the internal jugular vein
inferior to the carotid bifurcation it will travel between what two structures?
internal jugular vein and common carotid artery
where does the pharyngeal branch leave the vagus?
at the level of the inferior ganglion
what is the first thing the pharyngeal branch does upon leaving the vagus?
combines with fibers from the glossopharyngeal and with symathetic fibers from the sympathetic trunk
when the pharyngeal branch combines with glossopharyngeal and sympathetic trunk it form what?
pharyngeal plexus.. you should already known this
vagal fibers of the pharyngeal plexus will provide motor innervation to what?
pharyngeal constrictor muscles and the levator veli palatine muscle of the soft palate
what other branches besides the pharyngeal are given off at the inferior ganglion?
branches to the carotid
what do the branches of the carotid carry?
they carry viscerosensory fibers that relay information from chemoreceptors in the carotid body
where do the branches of the carotid carry the viscerosensory information to?
inferior part of the nucleus for the solitary tract
what nerve is given off just inferior to the inferior ganglion?
superior laryngeal nerve
what are the two divisions of the superior laryngeal nerve?
external laryngeal nerve
internal laryngeal nerve
what does the external laryngeal motor supply?
cricothyroid muscle
what does the internal laryngeal nerve sensory supply?
laryngeal mucosa as far inferior as the vocal folds
what does the recurrent laryngeal nerve motor supply?
supplies motor fibers to all muscles of the larynx, except the cricothyroid?
what nerve supplies the cricothyroid?
external laryngeal nerve
what does the recurrent laryngeal nerve sensory supply?
supplies from the larynx inferior to the vocal folds
what is the path of the recurrent laryngeal nerve of the left side?
comes off the vagus as it passes in front of the aortic arch, then passes under the aortic arch and ascends, eventually becoming the inferior laryngeal nerve
what is the path of the recurrent laryngeal nerve on the right side?
passes posteriorly under the subclavian artery before ascending
what fibers do the superior and inferior cervical cardiac branches?
parasympathetic information to the cardiac plexus
which cervical cardiac branch travels with the great vessels to the cardiac plexus?
the superior cervical cardiac branch
where does the inferior cervical cardiac branch come from?
its a branch off of the recurrent laryngeal nerve
one of the cervical cardiac branches will carry viscerosensory information concerning what?
pressure of the wall of the aorta.
when is the cervical cardiac branch carrying viscerosensory information of the pressure of the aorta wall stimulated?
the nerve is stimulated when the pressure becomes too high
as the vagus nerve enters the thorax and passes posterior to the root of the ipsilateral lung and contributes to what?
pulmonary plexus
after entering the thorax and contributing to the pulmonary plexus what is the path variations of the right and left vagus nerve?
the right passes posteriorly and the left passes anteriorly of the esophagus, contributing to the esophageal plexus
how does the right vagus nerve enter the abdmonial cavity?
through the esophageal opening
what does the right vagus nerve become when it enters the abdominal cavity?
becomes the posterior vagal trunk
the posterior vagal trunk sends branches to the posterior stomach which terminate where?
terminates in a large celiac branch
where does the large celiac branch send branches to?
duodenum
liver
kidneys
small intestine and proximal 2/3 of the large intestine
how does vagal supply reach the organs innervated by the the celiac branch?
through the celiac, superior mesenteric, and renal plexuses
what does the left vagal nerve become after entering the abdominal cavity?
anterior vagal trunk
how does the left vagus nerve enter the abdominal cavity?
esophageal opening
where does the anterior vagal trunk supply?
sends branches to the stomach, liver, pancreas and superior part of the duodenum
