The autonomic nervous system is the system regulating the internal processes proceeding in an organism: activity of sense organs, reductions and relaxations of smooth muscles, functioning of internals, blood and lymphatic system, glands. In addition, the autonomic nervous system "is responsible" for organism adaptation to the changing environmental conditions, for example, at fall of temperature it promotes acceleration of a metabolism, at increase – slows down it.
Exactly thanks to the autonomic nervous system (ANS) the main functions of an organism can normally be carried out: blood circulation, digestion, breath, metabolism, etc. Proceeding from it, it is easily possible to see what huge value it has.
The autonomic nervous system is subdivided into the central department which is localized in a head and spinal cord, and on peripheral department – its cages and fibers are located in all other parts of a human body.
The great ancient Roman doctor and the scientist Claudius Galen living in the 2nd century AD in the works published data of researches which can be considered the first mention of the autonomic nervous system. Then there came the long period of silence, and only in the 16th century researches VNS were resumed. For example, Vezaly (1514 — 1554) found out arrangement of a boundary nervous trunk. The modern name "autonomic nervous system" was entered after the publication of works Bichat, at the very beginning of the 19th century. Why vegetative nervous system is often called "autonomous"? This term was for the first time offered Langley in the 1908th year. The scientist wanted to emphasize thereby the fact of independence of VNS of so-called "somatic nervous system" (SNS). The autonomy consists also in the following feature of functioning of VNS. Nervous impulses pass on vegetative fibers much more slowly, than on somatic fibers. The fact is that fibers in a somatic nervous trunk are isolated from each other, and in vegetative fiber – no. Therefore the nervous impulses going on vegetative fibers can extend to the next fibers, and excitement of vegetative nervous fiber surely extends to the next bodies (that is extends not only deep into, but also in breadth). For this reason the emotions experienced by the person surely lead to change of its temperature, frequency of breath, pulse, etc. On this principle operation of known "lie detector" is also constructed. At the same time, between BHC and SNA there is, certainly, a close interrelation, both anatomic, and functional.