autonomic nervous system

Introduction

Component of the nervous system that represents motor innervation of smooth muscle, cardiac muscle & glands. It consists of 2 anatomically distinct, mutually antagonistic components:

• sympathetic nervous system
• parasympathetic nervous system In both systems, the pathway of innervation consists of a synaptic sequence of 2 motor neurons. One lies in the brainstem or spinal cord (presynaptic or preganglionic neuron); the other (postsynaptic or postganglionic neuron) lies in one of the autonomic ganglia outside of the central nervous system. Preganglionic fibers of (B-fibers) are thin, but myelinated. Postsynaptic fibers are unmyelinated. The neurotransmitter of the ganglionic synapses is acetylcholine.

More general terms

• organ system

More specific terms

• parasympathetic nervous system
• sympathetic nervous system
• vagal (nerve) trunk

Additional terms

• autonomic agent

Component of

• nervous system

Components

• white rami communicantes
• gray rami communicantes