A motor unit is defined as a motor neuron and all the muscle fibers that it controls. When a motor neuron fires, all the muscle fibers in the motor unit contract together. The size of a motor unit can vary depending on the muscle, with small motor units controlling fine, precise movements and large motor units controlling more powerful movements.

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Define motor Unit

Question 134

Multiple Choice

Define motor unit.

A) A motor unit is the sum total of all the motor neurons going to a specific muscle.
B) A motor unit is the sum total of all the muscle fibers in a whole muscle.
C) A motor unit is the maximum tension that a whole muscle can generate with maximum stimulation.
D) A motor unit is a motor neuron and all the muscle fibers that it controls.
E) A motor unit is the sensory neuron going away from and the motor neuron going to a skeletal muscle.

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