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20 Cards in this Set
- Front
- Back
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What type of fibers are in CN 7?
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-Mixed
-Has 2 efferent (motor) components and 2 afferent (sensory) components |
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How many nuclei are associated with CN 7
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4 nuclei in the brainstem
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Where is CN 7 located?
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Axons leave the brainstem at the pontomedullary junction, medial to CN 8
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What are the 2 efferent components of CN 7?
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-facial motor nucleus
-superior salivatory nucleus |
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What is the function of the facial motor nucleus?
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innervates the mimetic facial muscles (facial expression)
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What is the function of the superior salivatory nucleus?
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provides parasympathetic innervation to mediate lacrimation and salivation
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Where is the facial motor nucleus located?
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-Caudal Pons
-axons leaving the nucleus travel dorsally and medially and wrap around the abducens nucleus, then travel ventral and lateral to exit the brainstem |
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What is the input to the facial nucleus?
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recieves cortical motor input from the corticobulbar tract
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Discuss the divisions of the cortical input to the corticobulbar tract.
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-cortical input is divided so motor neurons innervating the upper part of the face recieve bilateral input from the cerebral cortex, and motor neurons innervating the lower part ofthe face recieve only contralateral input from the cerebral cortex
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Discuss the different indications of lesions to the facial motor nucleus.
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-lesions to the facial nucleus cause an ipsilateral paresis of the entire face
-lesions to the corticobulbar tract affect only the lower face |
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What are the 2 classes of motor neurons of facial motor control?
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-upper - tell lower motor neurons what to do
-lower - neuron which synapses on the muscle and tells it to contract |
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Where will muscle weakness be if the upper motor neuron is damaged?
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Contralateral facial weakness in the inferior portion of the face
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Where will the muscle weakness be if the lower motor neuron is cut?
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Contralateral facial weakness along that entire side of the face
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What type of nervous fibers arise from the superior salivatory nucleus?
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The facial nerve contains parasympathetic preganglionic axons that arise from the superior salivatory nucleus
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What ganglia do the preganglionic axons of the superior salivatory nucleus innervate?
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-pterygopalatine ganglion
-submandibular ganglion |
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Where do the fibers of the pterygopalatine ganglion go to?
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leads to lacrimation via the lacrimal glands
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Where do the fibers of the submandibular ganglion go to?
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leads to the salivation via the sublingual and submandibular glands
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What nerve is involved in taste?
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Cranial nerve 7 conducts gustatory information from the anterior 2/3 of the tongue
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Where are the cell bodies of the CN 7 nerve responsible for taste?
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these sensory neurons have their cell bodies in the geniculate ganglion and synapse in the solitary nucleus
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What are the somatic functin sof CN 7?
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-conducts somatic sensations from a small area within the pinna (ear)
-have cell bodies in the geniculate ganglion, synapse in teh spinal trigeminal nucleus |
