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Multiple Choice
A single neuron and all the muscle fibers it stimulates comprise a:
A
sarcomere
B
motor unit
C
myofibril
D
neuromuscular junction
Verified step by step guidance
1
Understand the anatomy of a motor unit: A motor unit consists of a single motor neuron and all the muscle fibers it innervates. This is the functional unit of muscle contraction.
Review the role of the neuromuscular junction: This is the site where the motor neuron communicates with the muscle fiber, but it is not the entire motor unit. It is a part of the motor unit.
Clarify the term sarcomere: A sarcomere is the smallest contractile unit within a myofibril, but it does not include the neuron or the muscle fibers stimulated by the neuron.
Define myofibril: Myofibrils are the thread-like structures within muscle fibers that contain sarcomeres. They are part of the muscle fiber but do not include the neuron.
Conclude that the correct term for a single neuron and all the muscle fibers it stimulates is 'motor unit,' as it encompasses both the neuron and the muscle fibers it innervates.