Glossopharyngeal Nerve Flashcards
Is the glossopharyngeal nerve a mixed, sensory or motor nerve?
Mixed nerve with both sensory and motor components
What are the 3 types of sensory fibers for the glossopharyngeal nerve?
Somatosensory neurons
Gustatory neurons
General Visceral Afferent neuons
Where are the cell bodies of primary somatosensory neurons of the glossopharyngeal nerve located?
Superior ganglion of IX nerve
Where are the peripheral processes of somatosensory neurons of glossopharyngeal nerve distributed?
Posterior 1/3 of tongue
Upper Pharynx
Tympanic Cavity
Eustachian tube
Where do the central processes of the somatosensory neurons of the glossopharyngeal nerve enter and terminate?
Enter brainstem, joins the spinal tract of the trigeminal nerve and terminate in the spinal trigeminal nucleus (2nd order neurons
Where do somatosensory neurons of the glossopharyngeal nerve travel from the spinal trigeminal nucleus?
Ascend to the VPM nucleus of the thalamus through the trigeminothalamic tract
Where do somatosensory neurons of the glossopharyngeal nerve travel from the spinal trigeminal nucleus?
Third order neurons of the VPM nucleus project axons through the posterior limb of the internal capsule and terminate in primary somatosensory cortex
What are somatosensory afferents of the glossopharyngeal nerve serve as in regards to the gag reflex?
The afferent limb of the gag reflex (response that occurs to touching posterior 1/3 of tongue or upper pharynx
What does the efferent limb of the gag reflex innervated by?
X nerve - palate and pharynx muslces
XII nerve - tongue uscles
V nerve - mastication
Where are the cell bodies of primary gustatory neurons of the glossopharyngeal nerve located?
Primary neurons cell bodies are found in the inferior ganglion of the IX nerve
Where are the peripheral processes of Gustatory neurons of glossopharyngeal nerve distributed?
Peripheral processes distributed through ligual branches of IX nerve to the posterior 1/3 of the tongue
Where do the central processes of the gustatory neurons of the glossopharyngeal nerve enter and terminate?
Central processes enter brainstem and terminate in the solitary nucleus (rostral part in the medulla
Where do gustatory neurons of the glossopharyngeal nerve travel from the solitary nucleus?
Fibers of the second order neurons ascend the brainstem through the ipsilateral central tegmental tract to terminate in the VPM nucleus of the thalamus
Where do gustatory neurons of the gloospharyngeal nerve poject axons of taste area?
Thalamic neurons project axns to the “taste area of the cerebral cortex located in the parietal lobe and insula
Where are the cell bodies of General Visceral neurons of the glossopharyngeal nerve located?
Cell bodies in the inferior ganglion of IX nerve
Where are the peripheral processes of General Visceral afferent neurons of glossopharyngeal nerve distributed?
To the carotid sinus (barception) and carotid body (chemoreception)
Where do the central processes of the General Visceral afferent neurons of the glossopharyngeal nerve enter and terminate?
Enter brainstem in IX nerve and descend in the medulla in the solitary tract and terminate in the solitary nucleus (caudal part)
What are the two motor components of the glossopharyngeal nerve?
Lower Motor Neurons
Autonomic
Where are the cell bodies of the somatomotor neurons of glossopharyngeal nerve found?
Ambiguosia medulla
What do the the somatomotor neurons of glossopharyngeal nerve innervate?
Stylopharyngeus
Will there be paralysis of the stylopharygeus muscle with a upper motor neuron lesion?
No paralysis of stylopharyngeus because the motor components receive bilateral corticobulbar innervation
Where are the parasympathetic neuron cell bodies of the glossopharyngeal nerve found?
Cell bodies comprise the inferior salivatory nucleus located in the medulla
Where do parasympathetic neurons of the glossopharygeal nerve terminate?
Fibers terminate in the otic ganglion (postganglionic parasympathetic)
Where do the postganglionic fibers of the glossopharyngeal nerve provide secretomotor innervation to?
Parotid gland
