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28 Cards in this Set
- Front
- Back
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What are teh 3 types of movement?
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1. tone
2. reflex 3. voluntary |
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What is tone and how is it tested?
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Tone is the steady contraction of skeletal fibers and is tested by passive stretching
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What occurs when command structures are damaged?
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paralysis (UMN/LMN)
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What occurs when control structures are damaged?
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ataxia/dyskinesia (Basal Ganglia/cerebellum)
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LMN or alpha motor neurons are the sole connection between...
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CNS and skeletal muscles (Final common pathway)
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What is included in LMN?
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brainstem and spinal motor neurons whose axons go to the PNS and synapse on extrafusal muscles
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LMN that are in the spine go to? LMN that are in the brainstem go to?
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spine go to the body
brainstem go to the head/neck |
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How are LMN organized in the spinal cord?
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Somatotopically in the anterior horn extending vertically through the spinal cord (how far depends on what level the limb is that they innervate)
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What CN (LMN) are located in the midbrain?
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CN III, IV
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What CN (LMN) are located in the pons?
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CN V (most rostral and lateral),
VI, VII (even with VI but more lateral) |
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What CN (LMN) are located in the medulla?
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Nucleus ambiguous (CN IX,X,XI~ lateral to XII)
CN XII (medial extending rostral and caudal to NA) |
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How is the Muscle spindle receptor alligned in the extrafusal skeletal muscle?
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in parallel
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The Muscle spindle receptor detects what?
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rate and amount of stretch
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LMN damage reults in what 3 things?
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1. flaccid paralysis
2. loss of reflexes 3. atrophy |
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What happens when there is an increase in muscle length?
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Intrafusal muscle spindle fibers sends this information via afferents to the dorsal root, synapses on LMN of anterior horn, exits via alpha motor axons, and contracts extrafusal fibers (muscle)
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What is the difference between Group Ia axons and Group II axons?
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Group 1a are larger, heavily myelinated and faster
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Dynamic nuclear bag fibers are in contact with what type of axons?
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Group Ia
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Static nuclear bag/nuclear chain fibers are innervated by what type of axons?
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Group Ia and Group II
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What is the purpose of gamma motor axons?
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Synapse at the polar regions of the spindle cells causing the intrafusal muscle elements to contract (resets the system)
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The number of APs propogataed by Group Ia afferents is directly correlated with?
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dynamic rate/velocity of change
and static amount of change |
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The number of APs propogated by Group II afferents is directly correlated with?
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magnitude of stretch
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What is the overall purpose of the Golgi Tendon Organ?
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protect muscles from excessive contraction (lift too much weight could harm musculoskeletal system)
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Golgi tendon organs are oriented in what manner with the muscle?
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in series
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Golgi Tendon organ senses?
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shortening of the muscle (contraction)
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What axon is in contact with the golgi tendon organ?
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group Ib
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The golgi tendon organ works by what type of circuit?
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Disynaptic circuit
The inhibitory neuron inhibits the alpha motor neuron so the muscle is relaxed rather than contracted |
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What is clonus?
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an oscillating pattern of rhythmic contractions and relaxations due to repetitive activation of stretch and golgi tendon organ reflexes
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Clonus demonstrate damage to what?
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Descending motor pathways
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