MICROANATOMY

Detailed explanation-1: -All muscle fibers in a motor unit are of the same fiber type. When a motor unit is activated, all of its fibers contract. In vertebrates, the force of a muscle contraction is controlled by the number of activated motor units.

Detailed explanation-2: -A motor unit consists of a neuron plus the muscle fibers it supplies. There are many motor units in a nerve that collectively provide electrical input to a muscle to generate a muscle contraction.

Detailed explanation-3: -: a nerve fiber whose stimulation causes muscular contraction.

Detailed explanation-4: -The three types of muscle fiber are slow oxidative (SO), fast oxidative (FO) and fast glycolytic (FG). SO fibers use aerobic metabolism to produce low power contractions over long periods and are slow to fatigue. FO fibers use aerobic metabolism to produce ATP but produce higher tension contractions than SO fibers.