Which statement is true regarding motor units? A) All muscle fibers within a motor unit contract when the motor neuron is activated B) A motor unit consists of multiple motor neuro... Which statement is true regarding motor units? A) All muscle fibers within a motor unit contract when the motor neuron is activated B) A motor unit consists of multiple motor neurons and their muscle fibers C) Motor units are always the same size regardless of muscle function D) Motor units do not influence contraction strength
Understand the Problem
The question is asking which statement about motor units is accurate. It aims to assess knowledge of muscle physiology and the role of motor units in muscle contraction.
Answer
All muscle fibers within a motor unit contract when the motor neuron is activated.
The correct statement is: A) All muscle fibers within a motor unit contract when the motor neuron is activated.
Answer for screen readers
The correct statement is: A) All muscle fibers within a motor unit contract when the motor neuron is activated.
More Information
In a motor unit, once the motor neuron is activated, all the muscle fibers it innervates will contract simultaneously. Motor units vary in size depending on the precision required by the muscle's function.
Tips
A common mistake is to assume that motor units consist of multiple motor neurons which is incorrect. A motor unit is comprised of a single motor neuron and the muscle fibers it innervates.
Sources
- Beta Motor Neuron - an overview | ScienceDirect Topics - sciencedirect.com
- Chapter 31: The Motor Unit and Muscle Action - Weizmann Institute - weizmann.ac.il
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