Once a motor neuron has fired,all the muscle fibers in a muscle contract.

Question

Quizplus · Accepted Answer

This statement is false. A motor neuron typically controls multiple muscle fibers, which makes up a motor unit. When a motor neuron fires, only the muscle fibers in that particular motor unit contract, not all the muscle fibers in the muscle. This is known as the all-or-none principle. Also, the force of the contraction can be modulated based on the number of motor units recruited by the brain.

Once a Motor Neuron Has Fired,all the Muscle Fibers in a Muscle