BearCh13-ACRQedt - Chapter 13 Spinal Control of Movement Answers to Chapter Review Questions Page 1 of 3 Question 1 What did Sherrington call

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Chapter 13 – Spinal Control of Movement Answers to Chapter Review Questions Page 1 of 3 Copyright © 2007. Lippincott Williams & Wilkins. Ancillary material to accompany Bear et al.: Neuroscience: Exploring the Brain, 3e Question 1: What did Sherrington call the “final common pathway,” and why? Answer: Sherrington called the lower motor neurons of the spinal cord the “final common pathway” that controls behavior. These motor neurons, also called the somatic motor neurons, directly command muscle contraction. They are the output of the motor system. Inputs to lower motor neurons include the sensory afferents entering the dorsal horn (providing information about muscle length), the upper motor neurons in the motor cortex, and the interneurons within the spinal cord that participate in spinal motor programs. Regardless of the source of the input, the output is the lower motor neurons, the final common path. Question 2: Define, in one sentence, motor unit. How does it differ from motor neuron pool? Answer: A motor unit consists of one alpha motor neuron and all the muscle fibers that the alpha motor neuron innervates. This is the elementary component of motor control. A motor neuron pool consists of all the alpha motor neurons that innervate a single muscle. Question 3: Which is recruited first, a fast motor unit or a slow motor unit? Why?
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This note was uploaded on 09/09/2009 for the course SPHSC 449 taught by Professor Peter during the Summer '09 term at University of Washington.

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BearCh13-ACRQedt - Chapter 13 Spinal Control of Movement Answers to Chapter Review Questions Page 1 of 3 Question 1 What did Sherrington call

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