Lesson 10: Throat Movements Flashcards
Where does the general sensory glossopharyngeal nerve receive input form?
Upper pharynx, tonsils, soft palate, posterior 1/3 of tongue, middle ear
What is the pathway of general sensory information in the glossopharyngeal nerve?
To the inferior ganglion, to the nucleus solitarius (medulla), to the ventral medial nucleus, to the sensory cortex
What is the role of the special sensory glossopharyngeal nerve?
Taste from the posterior 1/3 of the tongue and oral pharynx
What is the pathway of the special sensory information in the glossopharyngeal nerve?
Inferior ganglion to the rostral nucleus solitarius to the medial lemniscus, to the ventral posterior nucleus of the thalamus, to the primary sensory cortex
What are the two nuclei of the glosopharyngeal nerve?
The nucleus solitarius and the nucleus ambiguus
What does the glossopharyngeal nerve involuntarily control?
The parotid gland
What is the pathway of involuntary control in the glossopharyngeal nerve?
Inferior salivatory nucleus, to the parasympathetic fibers, to the otic ganglion, to the gland
What muscle is voluntary innervated by the glossopharyngeal nerve? What role does this muscle play?
The stylopharyngeus muscles - the swallowing reflex
What’s the pathway of voluntary motor control of the glossopharyngeal nerve?
Bilateral motor cortex, to the rostral nucleus ambiguus, to the ipsilateral stylopharyngeus muscle
What portion of the glossopharyngeal nerve is prone to injury, and why?
The central component, from a stroke
What are the symptoms of a UMNL to the glossopharyngeal nerve?
Swallowing difficulties
How are the glossopharyngeal and vagus nerves tested? What part of them is shown?
Touching the back of the throat to test the gag reflex
Shows afferent glossopharyngeal, efferent vagus nerve
Where is the vagus nerve nuclear complex? What does it consist of?
The ventricular floor of the medulla
The nucleus ambiguus, dorsal motor nucleus and nucleus solitarius
Where does the vagus nerve exist the brainstem?
In the lateral medulla, between the inferior olivary nucleus and the inferior cerebellar peduncle - through the jugular foramen
What pathway structures are shared by the glossopharyngeal and vagus nerve?
The inferior ganglia, nucleus solitarius, and nucleus ambiguus
Where does the vagus nerve receive sensory input from, both general and special?
Special: taste from the larynx and epiglottis
General: sensation from the larynx, thorax, carotid body, abdomen
Which nerves have their voluntary motor input in the nucleus ambiguus?
The vagus, glossopharyngeal and spinal accessory nerves
What is the pathway of general and special sensory information in the vagus nerve?
Inferior ganglion, to the nucleus solitaris, to the lateral lemniscus, to the VPM in the thalamus, to the parietal opercular sensory cortex
What does the vagus nerve involuntarily motor?
Cardiac and heart muscles, esophagus, stomach, glands
What is the pathway of involuntary motor control in the vagus nerve? What branch is this?
The main vagus nerve
Dorsal motor nucleus, to the parasympathetic fibres, to the distal ganglia
What does the vagus nerve voluntarily motor? What is the role of these muscles?
The pharynx, larynx and soft palate muscles
Phonation, swallowing, resonance, and respiration
What is the pathway of voluntary motor information in the vagus nerve?
From the bilateral cortex, to the posterior nucleus ambiguus, to the muscles
What is the role of the recurrent laryngeal branches of the vagus nerve? How does it accomplish this?
Phonation, via innervation of the intrinsic laryngeal muscles and the epiglottis
What is the difference in pathway between the left and right recurrent laryngeal branches?
Right: curves around the subclavian artery
Left: around the aortic arch
Why do ear infections cause stomach aches?
Stimulation of the eardrum via pain results in stimulation of the vagus nerve, which results in reflexive contraction of involuntary stomach muscles
What is the relation between an enlarged heart and a hoarse voice, in relation to the vagus nerve?
Stretches the left branch of the recurrent laryngeal branch, resulting in a loss of innervation to the larynx and a hoarse voice
What else can damage the left recurrent laryngeal branch of the vagus nerve?
Tumours in the neck
How is backup for the vagus nerve when a stroke occurs?
Some backup - but mostly is crossed
How can the voluntary motor vagus nerve be tested?
Say ‘ah’ - watch for equal rising of the palate, which will pull the uvula towards the intact side and away from the paralyzed side
What symptom is present in a LMNL vs a UMNL to the vagus nerve?
LMNL: paralysis ipsilateral
UMNL: paralysis contralateral
What is the role of the spinal accessory nerve?
Innervation of the trapezius and sternocleidomastoid muscles
What is the role of the vagus nerve?
Motor innervation of the pharynx and the larynx, and sensation of the larynx
How is the sternocleidomastoid muscle tested?
Direct chin downward, to the opposite side of testing - against resistance
How is the trapezius muscle tested?
Patient shrugs shoulder against resistance
What is the pathway of information in the spinal accessory nerve?
Contralateral motor cortex, to the nucleus ambiguus, through the foramen magnum, to the muscles
What is the difference between symptoms for a LMNL and a UMNL for the spinal accessory nerve?
LMNL: shoulder is weak
- trapezoid is completely paralyzed
UMNL: some backup to the nucleus ambiguus results in paresis
What is paresis?
Partial paralysis
What does the hypoglossal nerve innervate?
Voluntary motor innervation of the intrinsic tongue muscles
What is the pathway of information in the hypoglossal nerve?
Hypoglossal nucleus, out of the brainstem by way of medially of the olive, out of the skull via the hypoglossal canal, and to the tongue from below
What is the difference in symptoms between a LMNL and UMNL in the hypoglossal nerve?
LMNL: atrophy & wrinkling on the ipsilateral tongue - profound
UMNL: not as wrinkled and atrophied due to some backup from non-injured side
- swallowing & speech are still impaired
What could cause a LMNL in the hypoglossal nerve?
Lymph node surgery
How can the hypoglossal nerve be tested?
Via the genioglossus
Protude the tongue - if one side is damaged, that side will not protude
