Autonomic nervous system

Vegetative Nervous System, Visceral-Efferent System, Preganglionic Neurons, Postganglionic Neurons

It is usually said that the autonomic nervous system is the part of our nervous system that is beyond the control of the will and that regulates a large number of different intestinal functions.

The autonomic nervous system is divided into:
1/ a sympathetic (sympatheticus ) part
2/ a parasympathetic ( parasympatheticus ) part and in
3/ the enteric nervous system ("abdominal brain").

1/ and 2/ convey signal traffic from the central nervous system out to the various organ systems.

The connection between the central nervous system and a receiving organ consists, in principle, of two series-connected neuron types:
a/ preganglionary and
b/ postganglionic neurons.

a/ The cell bodies of the preganglionic neurons form nuclei in the central nervous system and their nerve fibers (axons) leave the central nervous system with different cranial and spinal nerves. Once outside the skull and vertebral column, the thin preganglionic nerve fibers, often on very difficult paths, reach their final stations, i.e. to the postganglionic nerve cells.

b/ The cell bodies of the postganglionic neurons form the autonomic/visceral-efferent ganglia.

The sympathetic part has, among other things, the ability to put the body on high alert alert; gives the "adrenaline rush".

Among other things, the parasympathetic part is involved in various excretory functions.

The enteric nervous system is responsible, more or less on its own, for the functions of the gastrointestinal tract.

Both sympaticus and parasympathetic have components in both the peripheral and central nervous systems.

When talking about the structure (anatomy) of the autonomic nervous system, it usually refers to its parts in the peripheral nervous system.

It is now common that the sensory impressions from the viscera (the visceral afference) are also included in the autonomic nervous system.

Previously, only the visceral efference (i.e. sympathetic and parasympatheticus) was counted as the autonomic nervous system.