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Chapter 12. Reflex & Voluntary Control of Posture & Movement
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A 48-year-old man was undergoing a thorough neurological exam after falling from a construction platform. The test included an evaluation of his deep tendon reflex. What are the elements of the deep tendon reflex?
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A. Golgi tendon organ, group Ib afferent fibers, spinal inhibitory interneuron, contralateral α-motor neuron, and extrafusal fibers of the skeletal muscle
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B. Golgi tendon organ, group II afferent fibers, spinal inhibitory interneuron, ipsilateral α-motor neuron, and intrafusal fibers of the skeletal muscle
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C. Group Ia sensory fibers originating in the contractile portion of the intrafusal fibers of the muscle spindle, spinal dorsal horn neuron, ipsilateral α-motor neuron, and extrafusal fibers of the skeletal muscle
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D. Group Ia sensory fibers originating in the central portion of the intrafusal fibers of the muscle spindle, ipsilateral α-motor neuron, and extrafusal fibers of the skeletal muscle
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E. Group II sensory fibers originating in the contractile portion of the intrafusal fibers of the muscle spindle, spinal inhibitory interneuron, ipsilateral α-motor neuron, and extrafusal fibers of the skeletal muscle
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When dynamic γ-motor neurons are activated at the same time as α-motor neurons to muscle,
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A. prompt inhibition of discharge in spindle Ia afferents takes place.
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B. clonus is likely to occur.
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C. the muscle will not contract.
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D. the number of impulses in spindle Ia afferents is smaller than when α discharge alone is increased.
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E. the number of impulses in spindle Ia afferents is greater than when α discharge alone is increased.
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The inverse stretch reflex
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A. occurs when Ia spindle afferents are inhibited.
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B. is a monosynaptic reflex initiated by activation of the Golgi tendon organ.
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C. is a disynaptic reflex with a single interneuron inserted between the afferent and efferent limbs.
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D. is a polysynaptic reflex with many interneurons inserted between the afferent and efferent limbs.
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E. uses type II afferent fibers from the Golgi tendon organ.
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A. initiated by innocuous stimulation of the skin.
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B. can lead to the appearance of clonus.
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