Question

describe the physiological functions of somatic motor neurons

Answer 1

Motor Neurons

The neural pathway that results in skeletal muscle contraction can be functionally divided into two main types of neurons – the upper motor neurons in the central nervous system and the lower motor neurons of the somatic nervous system.

somatic motor neurons, alpha motor neurons and lower motor neurons all mean the same thing.

• Somatic motor neurons synapse onto a group of muscle cells. Each somatic motor neuron controls hundreds, sometimes thousands of skeletal muscle cells.
• Lower motor neurons can be a part of cranial or spinal nerves. They innervate muscle fibers and directly cause their contraction.

There are three types of lower motor neurons – alpha, beta, and gamma.

Alpha motor neurons are thick, myelinated, multipolar nerve fibers that are involved in innervating most skeletal muscle fibers and causing their contraction.

Gamma motor neurons support the activity of alpha motor neurons by keeping muscle spindles taut.

Alpha motor neurons can receive signals from upper motor neurons for voluntary muscle movement. At the same time, they can receive input from sensory and inter neurons as well, in order to initiate reflex actions.

The number of alpha motor neurons innervating a single muscle depends on the extent of fine motor control required at the site. Therefore, the muscles of a finger will have substantially more alpha motor neurons associated with them than the muscles of the thigh or upper arm.