GENERAL HISTOLOGY

Detailed explanation-1: -The combination of an individual motor neuron and all of the muscle fibers that it innervates is called a motor unit. The number of fibers innervated by a motor unit is called its innervation ratio.

Detailed explanation-2: -A motor unit consists of one alpha motor neuron and all the extrafusal muscle fibers it innervates. The number of these muscle fibers can vary from 1 or 2 to 1000. If the number of muscle fibers innervated by a motor neuron is few, the motion produced by that muscle is more precise.

Detailed explanation-3: -A single action potential from a motor neuron will produce a single contraction in the muscle fibers of its motor unit. This isolated contraction is called a twitch. A twitch can last for a few milliseconds or 100 milliseconds, depending on the muscle type.