How many fibers are there per motor unit?
The number differs, 2,000 fibers per motor neuron
Not too many people know that a motor unit consists of one Alpha Motoneuron and all the muscle fibers it innervates. The main idea is that muscles differ in the number of motor units that they contain. There are so many differences when it comes to how many muscle fibers are within each unit. Anyway, muscles that require specificity of movement, such as muscles in charge of eye movement, have fewer fibers per unit. On the contrary, the muscles that are meant for less specific tasks, have more fibers. Needless to say, the number of motor units per muscle can change due to some important factors like aging, disease or injury.