NRSC 407

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NRSC 407 11/20/07 Motor Control General
Concepts Motor Unit Size Principle Spinal
Reflexes Central Pattern Generators
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Fig 33-1
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Fig 33-2
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Fig 33-3
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Fig. 22.19
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Fig 33-8
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Fig 33-10
What happens when you can see your hand?
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Fig 34-1
The Motor Unit
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Fig 34-2
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Fig 34-3
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Fig 34-4
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Fig 34-5
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Fig 34-8
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Fig 34-9
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How does the motor system cause increasing
tension?
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Fig 34-10
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Fig 34-11
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22-4
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Fig 34-12
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In-Class Excercise
Intracellular current injection cat spinal motor
neuron
Schwindt and Crill, In Handbook of the Spinal
Cord, 1984
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Motor Unit 1 a motorneuron all the muscle
fibers it innervates
Motor Units have different sizes and different
properties
Small Slow fatigue resistant Units
Large Fast fatigable Units
Intermediate Fast fatigue resistant
Force is generated by increasing frequency of
twitch And recruitment of larger motor units.
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Muscle Receptors Proprioception
Muscle Spindles Measure Stretch Golgi Tendon
Measures Tension
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Types of Motion Reflex.
Little or no Cortical Input but very fast.
Muscles can only PULL
Extensor Muscles open the joints. Flexor muscles
close or flex the joints.
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2
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Fig 36-2
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Fig 36-3
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Gamma Motor Neurons
Fig 36-9
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Fig 36-4
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Fig 36-5
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Fig 36-6
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2
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Rhythmic Movement
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22-12
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22-12
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22-11
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22-11
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Fig 37-1
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Fig 37-2
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Fig 37-3
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Fig 37-7