The sympathetic nervous system ( sympathetic ) or the sympathetic nervous system is adjacent to the parasympathetic nervous system , and the enteric nervous system (intestinal nervous system), part of the autonomic nervous system (also called autonomic nervous system). Most organs are controlled by the first two systems, which act as counterparts and complement each other and thus enable extremely fine involuntary regulation of organ activity. The sympathetic nervous system usually has an ergotropic effect within the framework of this overall control , that is, it increases the outwardly directed ability to act during actual or perceived stress (" fight-or-flight ").
The cell bodies of the so-called first neurons of the peripheral sympathetic nervous system (sympathetic root cells) are located in the thoracic and lumbar marrow ( thoraco-lumbar system ). The superordinate centers of the sympathetic nervous system are the hypothalamus , brain stem and formatio reticularis , which send impulses to the sympathetic root cells in the spinal cord.
These root cells are located in the lateral horn of the spinal cord and form the nucleus intermediolateralis. They send their fibers to clusters of nerve cells next to the spine , the paravertebral ganglia, which are connected to one another and, in their entirety, represent the sympathetic trunk ( sympathetic trunk ). This also extends into the area of the cervical spine ( called the cervical sympathetic nervous system there) and the sacrum . In humans there are three cervical ganglions: the upper ( ganglion cervicale superius ), the middle ( ganglion cervicale medium ), which is inconstant, and the lower cervical ganglion ( ganglion cervicale inferius ).
In the paravertebral ganglia, most of the sympathetic fibers are switched to a second neuron. The neurotransmitter is (as with the parasympathetic nervous system) acetylcholine . The second (postganglionic) neuron transmits its impulses to the target organ using norepinephrine . Exceptions are the transmission of impulses to the sweat glands and the adrenal medulla. This is also done by acetylcholine.
Some axons leave the trunk without switching and move to the prevertebral ganglia in the area of the aorta ( ganglion celiacum , ganglion mesentericum superius , ganglion mesentericum inferius ) or to ganglia in the wall of the organs to be supplied ( intramural ganglia).
The term was first used by the Danish (but active in Paris) anatomist Jacob Winslow ( Winsløw , 1669-1760) in connection with nervous activity and used in his textbook Exposition anatomique de la structure du corps humain . It is derived from the ancient Greek words συμπαθεῖν sympatheín "pity" and συμπάθεια sympátheia "sympathy" and was used in this way by the ancient Greek doctor Hippocrates (around 460-370 BC). The ancient Greek doctor Galenos (around 129-216 AD) assumed a kind of empathy between different parts of the body. See also the concept of sympathy in medical history .
The main target tissues of the sympathetic system are the smooth muscles of the blood vessels and glands . Like the other parts of the autonomic nervous system, the sympathetic controls vital processes. This regulation takes place largely without conscious awareness and can hardly be influenced at will.
Overall, the sympathetic system increases the performance of the organism (ergotropy). It puts the body in high motivation, prepares it for attack or flight or other extraordinary efforts (→ stress reaction ).
- Cardiac activity
- Blood pressure
- Blood circulation and tone of the heart and skeletal muscles
- Glycolysis (providing energy by breaking down carbohydrates )
- Metabolism .
To do this, it inhibits other processes that are not absolutely necessary for the immediate activity, such as B. bowel activity . In the skin, intestines and especially the kidneys, it reduces blood flow by constricting the vessels there .
It also has an impact on:
- Lung function (expansion of the bronchi )
- Bladder function (causes continence )
- Sex organs (among other things causes ejaculation in men and orgasm in women)
- inner eye muscles (dilated pupils, mydriasis )
- Secretion of the glands (increase in sweat gland secretion and adrenaline release in the adrenal medulla , decrease in salivary and pancreatic secretion ).
- Jörg Braun: Tips for station work. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Urban & Fischer, Munich 2016, ISBN 978-3-437-23763-8 , pp. 1–28, here: pp. 7 f. ( Head and cranial nerves , especially for Horner syndrome ).
- R. Olry: Winslow's contribution to our understanding of the cervical portion of the sympathetic nervous system . In: J Hist Neurosci . 5, No. 2, 1996, pp. 190-196. doi : 10.1080 / 09647049609525666 . PMID 11619046 .
- Corpus Hippocraticum : Regulations 14.
- Stanley Finger: Minds behind the brain. A history of the pioneers and their discoveries . Oxford University Press, 2000, ISBN 0-19-518182-4 , p. 46
- Hermann Triepel : The anatomical names. Your derivation and pronunciation . Edited by Robert Herrlinger . 26th edition. Published by JF Bergmann, Munich 1962, p. 72
- Peter Berlit: Clinical Neurology , Springer, 2012, ISBN 978-3-642-16920-5 , p. 483
- Erwin-Josef Speckmann, Jürgen Hescheler, Rüdiger Köhling: Physiology . 6th edition. Urban & Fischer, Munich 2013, ISBN 978-3-437-41319-3 , p. 676