Simple Introduction to the Autonomic Nervous System

Move your mouse over the diagram and click on the links for detailed organ information.

Schematic diagram comparing some anatomic and neurotransmitter features of autonomic and somatic motor nerves.
Only the primary transmitter substances are shown. Parasympathetic ganglia are found in or near the wall of the organ innervated. Note that some sympathetic postganglionic fibers release acetylcholine or dopamine rather than norepinephrine. The adrenal medulla, a modified sympathetic ganglion, receives sympathetic preganglionic fibers and releases epinephrine and norepinephrine into the blood.
(ACh, acetylcholine; D, dopamine; Epi, epinephrine; NE, norepinephrine; N, nicotinic receptors; M, muscarinic receptors.)

Adapted from Figure 6-1: StatRef Online Library: Basic and Clinical Pharmacology 8th ed. (2001)
by Michael Bolger, 8/26/01
Copyright(c) 2001 The McGraw Hill Companies, Inc. All rights reserved