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Flashcards in Vagus Nerve X Deck (24)
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1
Q

Where are LMN located and what do they innervate?

A

In nucleus ambiguus, they innervate the skeletal muscles of 1.) Soft palate

  1. ) Larynx
  2. ) Pharynx
  3. ) Vocalis muscle (true vocal cords)
2
Q

Where is Nucleus ambiguus located and list the CN that have LMN within it

A

Reticular formation,

Lower motor neurons of CN IX, CN X, cranial part of CN XI

3
Q

Where are the preganglionic parasympathetic cell bodies primarily located

A

Dorsal motor nucleus of X

4
Q

Axons of preganglionic parasympathetic cell bodies exit the medulla and synapse where?

A

Exit the medulla as rootlets of X and synapse on postganglionic neurons in visceral walls of glands, cardiac muscle, and smooth muscle of the thorax and abdomen

5
Q

Sensory fibers of CN X travel along what tract and end where?

A

Solitary tract and end in the solitary nucleus

6
Q

The sensory fibers of CN X traveling along the solitary tract carry pain and pressure from where?

A

Pharyx, larynx, thorax, and abdomen

7
Q

UMN innervate what bilaterally, making a unilateral lesion of the UMN not easily noticed.

A

the nucleus ambigous

8
Q

What are the important reflexes affiliated with CN X? (3)

A
  1. ) Carotid sinus reflex
  2. ) Carotid Body reflex
  3. ) Cough, gag, and vomiting reflexes
9
Q

What CN carries the efferent part of the carotid sinus reflex to the heart?

A

CN X

10
Q

What CN carries the afferent part of the carotid sinus reflex to the heart?

A

CN IX

11
Q

In regards to the Carotid sinus reflex where does the afferent limb originate?

A

From baroceptors along the carotid artery near the bifurcation into internal and external carotid arteries

12
Q

Afferent information is carried by fibers of CN IX to where?

A

The solitary nucleus, then relayed to the dorsal motor nucleus of X

13
Q

The efferent limb of the carotid sinus reflex arc innervates the heart to slow or speed up heart rate?

A

slow heart rate

14
Q

The Carotid body reflex involves chemoreceptor sensation from where?

A

Lung Bronchioles

15
Q

The one sensory (afferent) component of the Carotid Body Reflex synapses where?

A

In the “medullary respiratory center” (an area of reticular formation)

16
Q

What does the Carotid Body Reflex control?

A

Breathing Rhythm, the efferent limb is via decending info to spinal cord levels controlling inspiration (intercostals and diaphragm)

17
Q

The cough, gag and vomiting reflexes involve sensory fibers from where?

A
Oral/nasal cavity (CN IX)
The Gut (CN X)
18
Q

How does the cough, gag, and vomiting reflex work?

A

Sensory info is relayed to appropriate LMN in Nucleus Ambiguous and spinal cord and preganglionic parasympathetics in dorsal motor nucleus of X

19
Q

Do lesions of CN X result in sensory, motor, or both deficits?

A

Both sensory and motor deficits

20
Q

What do unilateral lesions of LMN in CN X result in?

A

Difficult in swallowing, hoarseness (dysphonia), inability to raise the soft palate on the IPSILATERAL side

21
Q

Lesions of preganglionic parasympathetic fibers of CN X cause what?

A

Disruption of some gut reflexes

22
Q

Lesions of the preganglionic parasympathetic fibers are less important for diagnosis of lesion location but are more significant in identifying what?

A

Deficits associated with the somatomotor LMN component

23
Q

Hyperactivity (excess firing) can cause what?

A

Excess gastric acid secretion = ulcers

24
Q

Large bilateral lesions of the medullary reticular formation can disrupt what?

A

Normal breathing rhythms and reflex control of vascular resistance to blood flow, resulting in a coma
—patients with this type of damage may need life support systems and have a poor prognosis