Synonyms in a broader sense
vegetative nervous system, spinal cord, nervous systemThe parasympathetic nervous system is the antagonist of the sympathetic nervous system and is – like the latter – a part of the vegetative (also: autonomous) nervous system. The autonomic nervous system is important for the control of our organs and glands, it is called autonomous because we cannot control it arbitrarily, it runs “alongside” without us being constantly aware of it (just think of breathing, digestion and sweating, for example). The parasympathetic nervous system is the resting part of the autonomic nervous system.
While the sympathetic nervous system prepares the body for stressful situations, it is used to “replenish” energy and for relaxation. When the parasympathetic nervous system becomes active, our body functions change in the following way:This explains how the parasympathetic nervous system works. Now it remains to be clarified where it is located and how its effect comes about.
- Lowering blood pressure
- Decrease the heart rate per time and the force with which the heart pumps (i.e. : reduced heart rate and contraction force)
- Narrowing of the airways
- Pupil constriction
- Reduced sweat secretion
- Increased saliva secretion
- Increased digestive activity
The parasympathetic nervous system – just like the sympathetic nervous system – is not a single location in the body, but is distributed over a rather large area. This is understandable, since it must reach many different organs. It is possible to distinguish one place of origin, i.e. the cells from which the flow of information emanates from the rail system, the cell extensions, which bring the information to where it should reach and act, namely to the recipients, the organs.
The parasymapthicus is a craniosacral system. Its cells of origin are thus located in the head area (cranium (Latin) = skull) and in the area of the sacrum (Os sacrum (Latin) = sacrum bone), which makes up the lowest part of the spinal column. These original cells are nerve cells (neurons) with long extensions.
There are two types of nerve cell extensions: The part of the parasympathetic nervous system that is located in the head area is part of the cranial nerves. For a better understanding of the further text, the cranial nerves will be briefly discussed here:
- The axon, of which each neuron has at most one, serves to transmit information from the cell body towards the body’s periphery
- The dendrites, of which most neurons have a multitude, serve the reception of information in the periphery and its transmission to the cell body
The cranial nerves are to the head what the spinal nerves are to the rest of the body. They serve to control the muscles (in the head, this is especially the mimic muscles, i.e. many small muscles in the facial area, which allow us humans a distinct mimic expression spectrum) and to perceive touches in the entire head area.
They also convey smell, taste, hearing and sight. Furthermore, they control all glands in their supply area. There are 12 cranial nerves, they are numbered with roman numerals from I (1) to XII (12).
Most have different qualities, i.e. a nerve is not only responsible for the perception of touch, but also for moving certain muscles. The following 4 cranial nerves have another task, they carry parasympathetic parts: What does this mean? This is the aforementioned cranial system of the parasympathetic nervous system.
Via these 4 nerves the cells of origin of the cranial part reach their target organs.
- III Oculomotor nerve
- VII Facial nerve
- IX Glossopharyngeal nerve
- XVagus nerve
The principle of the parasympathetic parts of the cranial nerves is always the same. The original cells are located in a cranial nerve nucleus (the place where cranial nerves originate or end) with a specific name (because every cranial nerve has one or more cranial nerve nuclei), their extensions pass through a ganglion (with pseudo-nonipolar nerve cells) where they are switched and then run to their recipient.
This recipient can be a gland or a muscle. In the head area, the recipients are not “whole” organs, such as liver or kidney. Since the following list of the names of the various cranial nerve nuclei, ganglia and recipients is very specific and detailed, it is only intended to be included in this text in tabular form (see below).
