Vagus nerve

Question 1

is the vagus nerve a motor, sensory or mixed nerve?

Answer 1

Mixed

Question 2

What are the 3 types of sensory fibers from the vagus nerve?

Answer 2

Somatosensory neurons
Gustatory neurons
general visceral afferent neurons

Question 3

Where are the cell bodies of the vagus nerve somatosensory neurons?

Answer 3

superior ganglion of the X nerve

Question 4

where are the peripheral processes of the vagus nerve distributed to?

Answer 4

1) some skin of the external ear
2) part of the external auditory
3) lower pharynx
4) larynx
5) upper esophagus

Question 5

What tract do the central processes of the somatosensory vagus nerve join and where does it terminate?

Answer 5

Central processes enter brainstem, join the spinal tract of the trigeminal nerve and terminate in the spinal trigeminal nucleus

Question 6

Where do the fibers of the vagus nerve carrying somatosensory information travel from the spinal trigeminal nucleus?

Answer 6

fibers of the second order neurons ascend to the VPM nucleus of the thalamus through the trigeminothalamic tract

Question 7

Where does somatosensory vagus information travel from the VPM nucleus?

Answer 7

neurons of VPM nucleus send fibers through the posterior limb of the internal capsule to the primary somatosensory cortex

Question 8

Where are the primary sensory neurons of the gustatory neurons of the vagus nerve found?

Answer 8

Primary sensory neurons in the inferior ganglion of the X nerve

Question 9

Where do the peripheral processes of the gustatory neurons of the vagus nerve innervate?

Answer 9

Taste receptors on the epiglottis

Question 10

Where do the central processes of the gustatory neurons terminate?

Answer 10

Solitary nucleus (rostral part)

Question 11

Where do the fibers of the gustatory neurons of the vagus nerve travel from the solitary nucleus?

Answer 11

Fibers ascend the brainstem through the ipsilateral central tegmental tract to terminate in the VPM nucleus of the thalamus

Question 12

Where do the gustatory neurons of the vagus information travel from the VPM nucleus?

Answer 12

Thalamic neurons project axons to the “taste” area of the cerebral cortex in the parietal love and insula

Question 13

Where are the primary sensory neurons of the general visceral afferent neurons of the vagus nerve found?

Answer 13

cell bodies in the inferior ganglion of the X nerve

Question 14

Where do the peripheral processes of the general visceral afferent neurons of the vagus nerve innervate?

Answer 14

1) baroreceptors in the aortic arch
2) chemoreceptors in the aortic arch
3) receptors in organs of the thoracic and abdominal cavities to monitor stretch or distension of hollow organs in the thoracic and abdominal cavities including the transverse colon

Question 15

Where do the central processes of the general visceral afferent neurons terminate?

Answer 15

descend in the medulla in the solitary tract and terminate in the solitary nucleus

Question 16

What are the two motor components of the vagus nerve?

Answer 16

Somatomotor (lower motor neurons)

parasympathetics

Question 17

Where are the primary neurons of the somatomotor neurons of the vagus nerve found?

Answer 17

Cell bodies located in the nucleus ambiguus in the medulla

Question 18

How do the fibers of the somatomotor neurons of the vagus nerve emerge from the brainstem?

Answer 18

1) part of the vagus nerve

2) as the cranial root of the spinal accessory nerve (provide X nerve innervation to muscles)

Question 19

Where do the motor fibers of the X nerve supply?

Answer 19

1) All muscles of the palate except tensor veli palatini
2) All pharynx muscles except stylopharyngeus
3) All intrinsic larynx muscles
4) Muscles of upper esophagus

Question 20

Does the somatomotor fibers of the X nerve contain unilateral or bilateral corticobulbar innervation?

Answer 20

Bilateral

Question 21

With an upper motor neuron unilateral lesion of the vagus nerve what happens?

Answer 21

no paralysis of muscles innervated by the X nerve

Question 22

Where are the primary neurons of the preganglionic parasympathetic neurons of the vagus nerve found?

Answer 22

cell bodies comprise the dorsal motor nucleus of the vagus in the medulla (some in the nucleus ambiguus)

Question 23

How do the fibers of the preganglionic parasympathetic neurons of the vagus nerve distributed and terminate?

Answer 23

Fibers are distributed with the vagus nerve and terminate in terminal or intramural ganglia in or near the organ they supply

Question 24

where are postganglionic fibers of the vagus nerve distributed to the visceral effector cells?

Answer 24

Smooth muscle, cardiac muscle and gland cells to thoracic and abdominal cavities. In the GI tract through to the transverse colon

Question 25

What occurs in a unilateral lesion of the vagus nerve?

Answer 25

ipsilateral paralysis of muscles of the pharynx, larynx and palate;
Horseness of voice
dyspnea
dysphagia

Question 26

What happens with the uvula during phonation with an ipsilateral lesion of the vagus nerve?

Answer 26

uvula deviates to the controlateral side in regards to the lesion

Question 27

What happens to the vocal folds with an ipsilateral lesion of the vagus nerve?

Answer 27

The ipsilateral vocal fold adducts

Question 28

What occurs in a bilateral lesion of the vagus nerve?

Answer 28

paralysis of muscles of larynx pharynx and palate

Question 29

What is the outcome of a bilateral lesion of the vagus nerve?

Answer 29

Often die because vocal folds dive inwards