A motor unit is
A) many myofibrils in a sarcolemma.
B) many motor end plates at a neuromuscular junction.
C) a motor neuron and the muscle fibers connected to it.
D) the functional unit of a muscle fiber.

Question

Quizplus · Accepted Answer

A motor unit consists of a motor neuron and the muscle fibers it connects to. The motor neuron releases the neurotransmitter acetylcholine at the neuromuscular junction, causing the muscle fibers to contract. A motor unit can contain anywhere from a few to many muscle fibers, depending on the muscle's need for fine or forceful movements. A myofibril is a structure within a muscle fiber, and a motor end plate is part of the neuromuscular junction. Neither of these alone constitutes a motor unit.

A Motor Unit Is