Chapter 15, Problem 1CYU

Which fibers in the motor division of the PNS are not myelinated?

Summary Introduction

To review:

The non-myelinated fibers in the motor division of the PNS.

Introduction:

Brain is the main organ of the body that controls and coordinates all the processes and the system is known as the nervous system. This system is comprised of the brain, the spinal cord, and the nerves originated from them or supplied throughout the body. The nerves or neurons are the structural unit of the nervous system that transmit information from the brain to various body parts, and from different body parts to the brain.

Explanation of Solution

The nervous system is divided into two categories, including the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS involves the brain and the spinal cord, whereas the PNS is represented by the cranial nerves arising from the brain and the spinal nerves originating from the spinal cord.

The PNS is further classified into: sensory (afferent) division and motor (efferent) division. The sensory division transmits impulses from the body parts to the CNS, whereas the motor division transmits impulses from the CNS to peripheral organs for the production of a response against the generated.

The motor division is classified into: the somatic nervous system (SNS) and the autonomic nervous system (ANS). The motor units in the autonomic nervous system include the transmission of impulse through the two-neuron pathway; the preganglionic and postganglionic axon.

The preganglionic axon cell body lies in the CNS and they form a synapse with the second that is the postganglionic axon. The postganglionic axon receives neurotransmitters from the synapse and enter into the visceral organs or the target sites. They are unmyelinated and thinner in nature.