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11 Cards in this Set
- Front
- Back
How many sensory pathways exist for the trigeminal system? What is the distinguishing feature for each?
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TWO pathways
-One pathway DESCENDS before crossing and the other crosses immediately |
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What structures are innervated by the trigeminal system?
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1. Cornea
2. Mucocutaneous tissues around mouth & nostrils 3. Oral & nasal mucosae, sinuses 4. Tongue, anterior 2/3, teeth, & gums 5. Dura of anterior & middle cranial fossae 6. Skin of face to the vertex except angle of jaw & parts of ear |
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Primary Sensory Neurons
Location of nerve cell bodies? How many nerve roots? What parts of the head periphery are NOT supplied by CN V? |
-Trigeminal ganglion
-3 nerve roots: Ophthalmic V-1, Maxillary V-2, Mandibular V-3 -Back of head & angle of the jaw |
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2nd-Order Trigeminal Neurons
-Location of neurons? |
-Principal (chief) trigeminal nucleus AND Spinal trigeminal nucleus (DESCENDING)
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What does the Principal trigeminal nucleus mediate?
What does the Spinal trigeminal nucleus mediate? |
Principal: Fine touch stimuli, joint position, & vibration
Spinal: pain & temp. |
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What type of neurons does the Spinal trigeminal tract contain?
To what levels does the Spinal nucleus descend? Lesions in what areas effect this nucleus? |
-Primary afferents that synapse in the spinal (descending) nucleus of V.
-extends caudally to C2-3 & is continuous with the dorsal horn. -caudal pons & medulla |
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What pathway do 2nd order neurons form? Where do they go?
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-Trigeminothalamic pathway to VPM
(ventroposteromedial thalamus) |
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3rd order neurons in thalamus
Location of projected axons? |
-Project to the Postcentral Gyrus
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Primary Somatosensory = Postcentral Gyrus.
-Where is the Input? Output? |
INPUT: from internal capsule from VPM & VPL for ALL ALC, DCML, & trigeminothalamic systems
OUTPUT: To Association Somatosensory Cortex |
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What happens when the Gyrus is injured?
Is temp perception affected? Is pain perception affected? |
-Diminished position sense & ability to discriminate size, texture, & shape.
-Temperature altered but not diminished -NO pain is not in this gyrus |
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Association Somatosensory Cortex
-What is its important functions? |
-Being able to recognize objects by palpation, stereognois (Astereognosis)
-Recognizing numbers written on their hand (Agraphesthesia) |