Question

Describe the major categories of peripheral sensory and motor fibers. EXplain in your own words.

Answer 1

Sensory nerve fibres in the peripheral nerves are the peripheral axonal process of neurons in the dorsal root ganglion.

The motor axons are the processes of anterior horn cells of the spinal cord.

The three types of peripheral nerves are motor, sensory and autonomic.

Peripheral sensory:

The peripheral nervous system is classified into two systems, the somatic nervous system and the autonomic nervous system. Each system contains afferent and efferent components:

The afferent components consist of sensory neurons running from receptors for stimuli to the central nervous system.

The efferent components consist of motor neurons running from the central nervous system to the effector organ.

Motor fibre:

A nerve fiber whose stimulation causes muscular contraction. A motor neuron is a neuron whose cell body is located in the motor cortex, brainstem or spinal cord and whose fiber projects to the spinal cord or outside of the cord to directly or indirectly control effector organs. There are two types of motor neuron:

-Upper motor neurons and

-Lower motor neurons

The axon or the motor fiber, from the lower motor neurons are efferent nerve fibers that carry signals from spinal cord to effectors. The three types of lower motor neurons are alpha motor neuron, beta motor neuron and gamma motor neuron.

There are three primary categories of lower motor neurons, which can be further divided in sub-categories as:

Somatic motor neurons.

Special visceral motor neurons

General visceral motor neurons.