ANATOMY
MUSCULOSKELETAL AND SOFT TISSUE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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For the fibres of a motor unit to contract, the electrical impulse must reach a certain threshold, or the fibre will not contract
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The threshold for any muscular contraction is the same
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For the fibres of a motor unit to contract, most of the threshold needs to be met, or no movement will occur
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Motor unit recruitment begins with small units to large units
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Detailed explanation-1: -The ‘All or None’ Law Each fibre within a motor unit contracts according to the all or none law. This principle states that when a motor unit receives a stimulus of sufficient intensity to bring forth a response, all the muscle fibres within the unit will contract at the same time, and to the maximum possible extent.
Detailed explanation-2: -The correct answer option is (B). According to the all-or-none principle, the electrical impulse or response strength will be maximum irrespective of the stimulus strength.
Detailed explanation-3: -The all or none principle means that signal transmission between neurons is not dependent on the strength of the stimuli but, rather, only that the initial threshold is met. In other words, neurons will either transmit an impulse over the synapse to the next neuron completely or not at all.