SYMPATHETIC AND PARASYMPATHETIC SYSTEMS
BLACK CHART (SOUGY)
SYMPATHETIC SYSTEM (left side in yellow)
PARASYMPATHETIC SYSTEM (right side in red)
Superior cervical ganglion
1st thoracic ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
i¢ Pelvic nerve
q¢ Meissner's and Auerbach's plexus
Sudoriparous gland (sweat gland)
SYMPATHETIC AND PARASYMPATHETIC SYSTEMS
Set up according to Collin (L'organisation Nerveuse), and with his authorization, this chart is an essay of the systemization of the nerve pathways concerning the involuntary organs. (The sensation pathways are not represented.) An attempt has been made to update the original translation.
Represented in the middle, in white, are the diverse organs of the sympathetic and parasympathetic systems. On the left (A), in yellow, is the sympathetic system and on the right (B), in red, is the parasympathetic system.
The sympathetic system contains 2 sympathetic trunks or chains of lateral ganglia, which lie on either side of the vertebral column. Lateral ganglia are connected to the spinal cord by the rami communicantes. (The chart does not show this connection--check text diagram). Leaving from these ganglia is a series of nerves, comprised of little or no myelin, which reach the organs by the intervention of a complicated network of plexuses and ganglia. Only one of the 2 chains of lateral ganglia is represented in the chart. The same organs also submit to action of the parasympathetic neurons coming from the brainstem. The parasympathetic neurons are associated with specific cranial nerves. Involved are cranial nerves 3, 7, 9, & 10. There is also parasympathetic innervation from the sacral portion of the spinal cord.
In both systems and contrary to what one sees in the cerebro-spinal system, the effector pathway is not constituted by a unique neuron that innervates an organ, but by 2. The first neuron called the preganglionic neuron goes to a ganglion. The second neuron called a postganglionic neuron goes to the organ or structure of innervation. Within the ganglion, a synapse is found between the preganglionic neuron and the second, postganglionic neuron.
Within the sympathetic system, the ganglia are the lateral ganglia of the sympathetic trunk or chain including 3 cervical represented here by the superior cervical ganglion (a), 12 thoracic (shown here is the 1st thoracic or stellate ganglion (b), 4 lumbar and 4 sacral ganglia. Also shown are the collateral ganglia adjoining the organs: the celiac ganglion (c), which is commonly referred to as the "solar plexus", the superior mesenteric ganglion (d), and the inferior mesenteric ganglion (e).
In the parasympathetic system, the postganglionic neurons are always from terminal ganglia adjoining organs. They are arranged in a column in the chart but are not found in a chain. Terminal ganglia are distributed randomly. The following are examples of terminal ganglia: (f) is the ciliary ganglion that receives nerve fibers from the oculomotor nerve (3). (g) is the submaxillary ganglion that receives nerve fibers from the tympanic chord, coming off the facial nerve (7). (h) is the otic ganglion that receives fibers accompanying the glossopharyngeal nerve (9). The next ones in the chart belong to the pneumogastric system, of vagus (10) innervation. They were set up and labeled according to the names of the organs involved. Finally ( ) the hypogastric ganglion which receives the pelvic nerve ( ') coming from the parasympathetic sacral region.
The cell bodies of postganglionic neurons are all represented. The cell bodies of the preganglionic neurons are not represented in this chart. They are found in the regions of the lateral grey column of the thoracic or lumbar spinal cord for the sympathetic system and the midbrain , pons, medulla, and sacrum for the parasympathetic system. Hence, new terms have been given to designate these systems: thoracolumbar outflow for the sympathetic system and craniosacral outflow for the parasympathetic system.