Cranial Nerve IX and X Flashcards
True or False:
You very rarely get damage to just CN IX or X due to their close proximity
True
Where do the lower 4 cranial nerves arise
From the medulla
What are the lower 4 cranial nerves involved in (2)
- Pharyngeal and laryngeal function
2. Movements of the neck and tongue
What does damage to some of the lower 4 cranial nerves usually manifest as
Problems with speech and swallowing
How do the lower 4 cranial nerves typically get damaged
Damage to the medulla via a mass lesion
What 2 things cause anoxia to the brain
- Heart attack
2. Drowning
What does the corticospinal tract control
Voluntary movements of the torso and UE/LE
What does the corticobulbar tract control
Voluntary movements of the head and neck
Where does the corticobulbar tract travel in the internal capsule
Genu
Where does the corticobulbar tract arise
The lateral aspects of the primary cortices
True or False:
The corticobulbar tract contains UMN of non-oculomotor cranial nerves
True
Where does the corticobulbar tract terminate
Cranial nerves (LMNs)
True or False:
Some of the contacts of the corticobulbar tracts on the cranial nerves are direct and some are indirect through interneurons of the reticular formation
True
True or False:
Most corticobulbar innervation of cranial nerves is bilateral
True
What is the exception to corticobulbar innervation of cranial nerves being bilateral
Cranial nerve XII and below the eyes innervation of CN VII
True or False:
A LMN is anywhere a cortical neuron synapses
True
What happens when there is unilateral lesion of the cortex that serve the cranial motor nerves
Paralysis of the muscles of the face and head does not occur it causes mild forms of weakness in the affected muscles
Where are the cell bodies located for an UMN and LMN
UMN: In a CNS processing center/motor cortex or nucleus in brainstem
LMN: Nucleus of the spinal cord or brainstem
What are the only LMN axons that extend outside of the CNS
Ventral column
True or False:
Both CN IX and X have superior and inferior ganglia
True
Where does the glossopharyngeal nerve emerge
From the upper ventrolateral medulla
Where do the fibers of the glossopharyngeal nerve leave or enter the skull
The central part of the jugular foramen
Where are the superior and inferior ganglia of CN IX lie
In the jugular foramen
What does CN IX share most of it’s nuclei with (3)
CN V, VII, X
What are the motor nuclei of the glossopharyngeal nerve (2)
- Nucleus ambiguus
2. Inferior salivatory nucleus
What does the nucleus ambiguus innervate for CN IX
Stylopharyngeus muscle
What does the inferior salivatory nucleus innervate for CN IX
Parasympathetic innervation of the parotid gland
What are the sensory nuclei of the glossopharyngeal nerve (3)
- Trigeminal nuclei
- Rostral nucleus solitarius
- Caudal nucleus solitarius
What does the trigeminal nuclei innervate for CN IX (3)
- Somatic sensation from the middle ear
- Pharynx
- Posterior 1/3 of tongue
What does the rostral nucleus solitarius innervate for CN IX
Gustation posterior 1/3 of tongue
What does the caudal nucleus solitarius innervate for CN IX
Chemo and baroreceptors of the carotid body
What is the only nucleus innervated by the glossopharyngeal nerve
Inferior salivatory nucleus
What are the peripheral ganglion of the glossopharyngeal nerve (3)
- Otic ganglion
- Superior glossopharyngeal ganglion
- Inferior glossopharyngeal ganglion
True or False:
Taste and touch sensation at the back of the throat can trigger the gag reflex
True
What are the 2 other names for the gag reflex
- Pharyngeal reflex
2. Laryngeal spasm
What is the gag reflex
Contraction of the back of the throat triggered by stimulation by flavor or object touching the roof of the mouth, back of tongue, area around tonsils, or back of throat
What cranial nerve triggers the contraction for the gag reflex
Cranial nerve X
What cranial nerve senses the stimuli leading to the contraction
Cranial nerve IX
What does the gag reflex do
Prevents something from entering the throat except as part of normal swallowing
When does the gag reflex start to diminish
6-7 months of age
What does the gag reflex starting to diminish at 6-7 months mean
Basis for saying start feeding the baby solid food at this time frame
What can lesion to the glossopharyngeal nerve cause (7)
- Difficulty swallowing
- Impairment of taste over posterior 1/3 of tongue, palate, and pharynx
- Impaired sensation over the posterior 1/3 of the tongue, palate, and pharynx
- Absent gag reflex
- Dysfunction of the parotid gland
- Loss of sensation in external auditory meatus
- Possible tachycardia or bradycardia
True or False:
The vagus nerve is almost all sensory (parasympathetic of body)
True
True or False:
The vagus nerve has the longest course of all the cranial nerves
True
Where does the vagus nerve extend to and from
The head to the abdomen
What does the latin of vagary mean
Wandering
In the head and neck what is the vagus mainly responsible for (4)
- Ability to swallow
- Gag reflex
- Some taste
- Part of phonation
What is phonation
Production of speech sounds
What percent of the nerve fiber in the vagus nerve are dedicated to communication sensory info about the stat of your viscera up to your brain
80-90%
Where do the fibers of the vagus nerve enter or leave the skull
The central portion of the jugular foramen
Below the inferior ganglion what is the vagus nerve joined by
The cranial part of the accessory nerve (CN XI)
True or False:
The vagus nerve is functionally diverse and pathology of the vagus nerve is implicated in many clinical cases
True
What are the 2 motor nuclei of the vagus nerve
- Nucleus ambiguus
2. Dorsal motor nucleus of CN X
What does the nucleus ambiguus innervate for the vagus nerve (2)
- Laryngeal muscles
2. Pharyngeal muscles
What pharyngeal/laryngeal muscle does the vagus nerve not innervate
Stylopharyngeus
What does the dorsal motor nucleus innervate for the vagus nerve
Parasympathetic innervation of the heart, bronchi, and digestive tract
How far down the digestive tract does the vagus nerve innervate
To the splenic flexure
What are the 3 sensory nuclei of the vagus nerve
- Trigeminal nucleus
- Rostral nucleus solitarius
- Caudal nucleus solitarius
What does the trigeminal nucleus innervate for the vagus nerve
Somatic sensation from the pharynx, meninges, and small region of external auditory meatus
What does the rostral nucleus solitarius innervate for the vagus nerve
Taste of the epiglottis and pharynx
What does the dorsal nucleus solitarius innervate for the vagus nerve
Chemo and baroreceptors of the aortic arch
What is the only nucleus of the vagus nerve only
Dorsal motor nucleus
What are the 3 peripheral ganglia of the vagus nerve
- Parasympathetic ganglia in end organs
- Superior vagal ganglion
- Inferior vagal ganglion
What does vagus nerve lesions lead to paralysis of (3)
- Palate
- Pharynx
- Larynx
What does the paralysis of the palate, pharynx, and larynx lead to (5)
- Hoarseness
- Loss of gag reflex
- Loss of effective cough
- Swallowing problems (dysphagia)
- Choking
What autonomic dysfunctions occur due to vagus nerve lesions (6)
- Failure of soft palate elevation
- Deviation of uvula away from side of the lesion
- Abnormalities of esophageal motility
- Abnormalities of gastric acid secretion
- Abnormalities of gallbladder emptying
- Abnormalities of heart rate
What does damage to the recurrent laryngeal nerve of the vagus nerve cause if bilaterally damaged (3)
- Airway obstruction
- Aphonia (loss of voice)
- Stridor (inspiratory wheeze
What does damage to the recurrent laryngeal nerve of the vagus nerve cause if unilaterally damaged (1)
Dysphonia (difficulty speaking)