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18 Cards in this Set
- Front
- Back
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What is the purpose of the propriospinal system of neurons (spinal interneurons)
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- all movements require LMN at more than one spinal segment, interneurons integrates all of these together (integrate and distribute descending commands to move)
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Describe the long propriospinal neuron (location, influence, muscles)
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- axend/descend in the anterior fasiculus proprius (medial gray matter) entire spinal cord
- bilateral influence - medial neurons for axial muscles |
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Describe the intermediate propriospinal neurons (location, influence, muscles)
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- extend short distances in ventral part of the anterior horn
- proximal muscles of limbs |
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Describe the short propriospinal neurons (location, influence, muscles)
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- cervical and lumbosacral enlargments only for a few segments
- lateral anterior horn - more distal muscles of limbs |
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What are the 3 brainstem supraspinal centers?
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1. vestibular nuclei
2. reticular nuclei 3. red nuclei |
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Location of the vestibular nuclei
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ponto medullary junction in the lateral floor of the 4th ventricle
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What are the 2 tracts of the vestibular nuclei and what do they facilitate?
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1. Lateral vestibulospinal tract- extensor muscles ipslateral limbs
2. Medial vestibulospinal fibers- via MLF influence vertebral column and proximal limbs bilaterally |
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Location of the red nuclei
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tegmentum of midbrain at level of the superior colliculus
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What is the 2 main input sources to the red nucleus?
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1. cerebral cortex
2. cerebellum |
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What are the 2 main output of the red nucleu
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1. large rubrobulbar tract
2. small rubrospinal tract |
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What is the path of the output of the red nucleus and what do they do?
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They cross immediately, descend through the brainstem and facilitate flexor muscles of contralateral upper limb
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Where are the 2 regions of the reticular formation located?
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- ventro-medial in to the 4th ventricle in the medulla and pons
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What fibers are found in each of the 2 divisions of the reticular formation?
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Medullary= lateral reticulospinal fibers
Pons= medial reticulospinal fibers |
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What are the 3 main groups of the spinal cord?
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1. ventromedial
2. lateral 3. cortical |
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The ventromedial group consists of what fibers, location, and what is their purpose?
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Fibers: medial vestibulospinal and medial reticulospinal
Located: anterior funiculus (medial white matter) PUrpose: bilaterally influence axial muscles |
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The lateral group consists of what fibers, location, and purpose?
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Fibers: rubrospinal, lateral reticulospinal, lateral vestibulospinal
Located: central/lateral parts of anterior horn Purpose: influence proximal/distal limbs |
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The cortical group consists of what fibers, location, and purpose?
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Fibers: LCST (the UMN)
Located: dorsolateral part of ant horn (the LCST) Purpose: highly skilled (the UMN are the only ones that influence hand movements) |
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Why are axial/proximal/some distal limbs able to have partial recovery after a postcapsular lesion but not the hands?
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- The axial to distal limbs are also influenced by the vestibular/red/reticular areas and not solely by the UMN/Corticospinals
- Hand movements are solely innervated by UMN/ Corticospinals |
