Question

What is a motor unit?

Answer 1

Motor unit consists of a single afferent motor neuron that helps to carry the impulse away from the central nervous system and carry it to all of the muscle fibres and other organs that supply nerves.

Complete answer:
Motor neurons are the skeletal muscle fibres that are stimulated by the neuron's axon terminals. The muscle fibres present in the motor unit are of the same fibre type and the units get activated when the fibres contract. A group of motor units worked together for the coordination and contraction of a single muscle which is known as a motor pool and was proposed by Charles Scott Sherrington. Muscle fibres vary in number within a particular muscle and from muscle to muscle which acts on the largest body masses that consist of the motor units and more muscle fibres as compared to the smaller muscles which contain fewer muscle fibres in each motor unit.
A single motor neuron is present in most of the metal extra fuses skeletal muscle fibres and they branch within muscles to synapse on many different fibres which are typically distributed over certain areas in a muscle and ensure the contractile force of the motor unit gets spread evenly throughout the surface. This arrangement affects some of the motor neurons that bring the threshold of the muscle fibres when it contracts and activates to move and the motor neurone varies in size.

Note:
Motor units are of three types which consist of different physiological properties and other staining properties. Lubricants are the smallest motor units that are present in the muscles and produce gradations of force. The thigh muscle consists of the largest motor units.