The parasympathetic part of the nervous system is subdivided into the head and sacral regions. The head section (pars cranialis) includes the autonomic nuclei and parasympathetic fibers of the oculomotor (III pair), facial (VII pair), glossopharyngeal (IX pair) and vagus (X pair) nerves, as well as the ciliary, pterygopalatine, submandibular, sublingual, ear and other parasympathetic nodes and their branches. The sacral (pelvic) part of the parasympathetic part is formed by the sacral parasympathetic nuclei (nuclei parasympathici sacrales) II, III and IV sacral segments of the spinal cord (SII-SIV), internal pelvic nerves (nn.splanchnici pelvini), their parasympathetic pelvic nodes (gariglia) branches.

1. Parasympathetic part of the oculomotor nerverepresented by an additional (parasympathetic) nucleus (nucleus oculomotorius accessorius; the nucleus of Yakubovich-Edinger-Westphal), the ciliary node and processes of cells, the bodies of which lie in this nucleus and the node. The axons of the cells of the accessory nucleus of the oculomotor nerve, which lies in the tectum of the midbrain, pass through this cranial nerve in the form of preganglionic fibers. In the cavity of the orbit, these fibers are separated from the lower branch of the oculomotor nerve in the form of an oculomotor root (radix oculomotoria; short root of the ciliary node) and enter the ciliary node in the back, ending on its cells.

Ciliary node (ganglion ciliare)

Flat, about 2 mm long and about 2 mm thick, is located near the superior orbital fissure in the thickness of the fatty tissue at the lateral semicircle of the optic nerve. This node is formed by the accumulation of bodies of the second neurons of the parasympathetic part of the autonomic nervous system. The preganglionic parasympathetic fibers that have come to this node as part of the oculomotor nerve end in synapses on the cells of the ciliary node. Postganglionic nerve fibers as part of three to five short ciliary nerves emerge from the front of the ciliary node, go to the back of the eyeball and penetrate into it. These fibers innervate the ciliary muscle and the sphincter of the pupil. The fibers passing through the ciliary node transit general sensitivity (branches of the nasal nerve), forming a long (sensitive) root of the ciliary node. Sympathetic postganglionic fibers (from the internal carotid plexus) also transit through the node.

1. Parasympathetic part of the facial nerveconsists of the upper salivary nucleus, pterygopalatine, submandibular, sublingual nodes and parasympathetic nerve fibers. The axons of the cells of the superior salivary nucleus, which lies in the bridge lining, pass in the form of preganglionic parasympathetic fibers as part of the facial (intermediate) nerve. In the area of \u200b\u200bthe knee of the facial nerve, part of the parasympathetic fibers is separated in the form of a large stony nerve (n. Petrosus major) and leaves the facial canal. The large petrosal nerve lies in the eponymous groove of the temporal bone pyramid, then pierces the fibrous cartilage that fills the ragged opening at the base of the skull, and enters the pterygoid canal. In this canal, the large petrosal nerve, together with the sympathetic deep petrosal nerve, forms nerve pterygoid canal,which goes into the pterygo-palatine fossa and goes to the pterygopalatine node.

Pterygopalatine node (gangion pterygopalatinum)

4-5 mm in size, irregular in shape, located in the pterygoid fossa, below and medial to the maxillary nerve. The processes of the cells of this node - postganglionic parasympathetic fibers join the maxillary nerve and then follow as part of its branches (nasopalatine, large and small palatine, nasal nerves and pharyngeal branches). From the zygomatic nerve, parasympathetic nerve fibers pass into the lacrimal nerve through its connecting branch with the zygomatic nerve and innervate the lacrimal gland. In addition, the nerve fibers from the pterygo-palatine node through its branches: nasopalatine nerve (n.nasopalatine), large and small palatine nerves (nn.palatini major et minores), posterior, lateral and medial nasal nerves (nn.nasales posteriores, laterales et mediates), pharyngeal branch (r. pharyngeus) - are directed for innervation of the glands of the mucous membrane of the nasal cavity, palate and pharynx.

That part of the preganglionic parasympathetic fibers that are not included in the petrosal nerve departs from the facial nerve as part of its other branch - the drum string. After the tympanic string is attached to the lingual nerve, the preganglionic parasympathetic fibers go in its composition to the submandibular and hypoglossal nodes.

Submandibular node (ganglion submandibulare)

Irregular, 3.0-3.5 mm in size, located under the trunk of the lingual nerve on the medial surface of the submandibular salivary gland. In the submandibular node lie the bodies of parasympathetic nerve cells, the processes of which (postganglionic nerve fibers) in the glandular branches are sent to the submandibular salivary gland for its secretory innervation.

In addition to the indicated preganglionic fibers of the lingual nerve, the sympathetic branch (r. Sympathicus) from the plexus located around the facial artery approaches the submandibular node. In the composition of the glandular branches there are also sensitive (afferent) fibers, the receptors of which lie in the gland itself.

Sublingual node (ganglion sublinguale)

Unstable, located on the outer surface of the sublingual salivary gland. It is smaller than the submandibular node. The preganglionic fibers (nodal branches) from the lingual nerve approach the sublingual node, and the glandular branches branch off from it to the salivary gland of the same name.

1. Parasympathetic glossopharyngeal nerveformed by the lower salivary nucleus, ear node and processes of the cells lying in them. The axons of the lower salivary nucleus, located in the medulla oblongata, as part of the glossopharyngeal nerve, leave the cranial cavity through the jugular foramen. At the level of the lower edge of the jugular foramen, the prenodal parasympathetic nerve fibers branch off as part of the tympanic nerve (n. Tympanicus), which penetrates into the tympanic cavity, where it forms a plexus. Then these preganglionic parasympathetic fibers leave the tympanic cavity through the cleft of the canal of the small stony nerve in the form of the same nerve - the small stony nerve (n. Petrosus minor). This nerve leaves the cranial cavity through the cartilage of the laceration and approaches the ear node, where the preganglionic nerve fibers end on the cells of the ear node.

Ear node (ganglion oticum)

Rounded, 3-4 mm in size, adjacent to the medial surface of the mandibular nerve under the foramen ovale. This node is formed by the bodies of parasympathetic nerve cells, the postganglionic fibers of which are directed to the parotid salivary gland as part of the parotid branches of the ear-temporal nerve.

1. The parasympathetic part of the vagus nerveconsists of the posterior (parasympathetic) nucleus of the vagus nerve, numerous nodes that are part of the organ vegetative plexuses, and cell processes located in the nucleus and these nodes. The axons of the cells of the posterior nucleus of the vagus nerve, located in the medulla oblongata, are part of its branches. Preganglionic parasympathetic fibers reach the parasympathetic nodes near and intraorgan autonomic plexuses [cardiac, esophageal, pulmonary, gastric, intestinal and other autonomic (visceral) plexuses]. The cells of the second neuron of the efferent pathway are located in the parasympathetic nodes (ganglia parasympathica) of the near and intraorgan plexuses. The processes of these cells form bundles of postganglionic fibers that innervate the smooth muscles and glands of the internal organs, neck, chest and abdomen.
2. Sacral part of the parasympathetic part of the autonomic nervous systemrepresented by sacral parasympathetic nuclei located in the lateral intermediate substance of the II-IV sacral segments of the spinal cord, as well as by the pelvic parasympathetic nodes and processes of the cells located in them. The axons of the sacral parasympathetic nuclei emerge from the spinal cord as part of the anterior roots of the spinal nerves. Then these nerve fibers go as part of the anterior branches of the sacral spinal nerves and, after they exit through the anterior pelvic sacral foramen, they branch off, forming the pelvic visceral nerves (nn. Splanchnici pelvici). These nerves approach the parasympathetic nodes of the lower hypogastric plexus and the nodes of the autonomic plexus located near the internal organs or in the thickness of the organs themselves located in the pelvic cavity. The preganglionic fibers of the pelvic visceral nerves end on the cells of these nodes. The processes of the cells of the pelvic nodes are postganglionic parasympathetic fibers. These fibers are directed to the pelvic organs and innervate their smooth muscles and glands.

Neurons originate in the lateral horns of the spinal cord at the sacral level, as well as in the autonomic nuclei of the brain stem (nuclei IX and X of the cranial nerves). In the first case, the preganglionic fibers approach the prevertebral plexuses (ganglia), where they are interrupted. From here, postganglionic fibers begin, heading to tissues or intramural ganglia.

Currently, there are also intestinal nervous system (this was pointed out back in 1921 by J. Langley), which differs from the sympathetic and parasympathetic systems, in addition to being located in the intestine, is as follows:

1. intestinal neurons are histologically different from neurons of other autonomic ganglia;
2. in this system, there are independent reflex mechanisms;
3. ganglia do not contain connective tissue and blood vessels, and glial elements resemble astrocytes;
4. have a wide range of mediators and modulators (angiotensin, bombesin, cholecystokinin-like substance, neurotensin, pancreatic polypeptide, enfecalins, substance P, vasoactive intestinal polypeptide).

Adrenergic, cholinergic, serotonergic mediation or modulation is discussed, and the role of ATP as a mediator (purinergic system) is shown. AD Nozdrachev (1983), who designates this system as metasympathetic, believes that its microganglia are located in the walls of internal organs with motor activity (heart, digestive tract, ureter, etc.). The function of the metasympathetic system is considered in two aspects:

1. a transmitter of central influences to tissues and
2. independent integrative education, including local reflex arcs, capable of functioning with complete decentralization.

The clinical aspects of studying the activity of this department of the autonomic nervous system are difficult to isolate. There are no adequate methods for its study, except for the study of the biopsy material of the large intestine.

This is how the efferent part of the segmental vegetative system is built. The situation is more complicated with the afferent system, the presence of which, in essence, was denied by J. Langley. Several types of autonomic receptors are known:

1. pressure-sensitive and stretching-like bodies;
2. chemoreceptors, which perceive chemical shifts; thermo- and osmoreceptors are less common.

From the receptor, fibers go, without interruption, through the prevertebral plexuses, the sympathetic trunk to the intervertebral node, where afferent neurons are located (together with somatic sensory neurons). Further, the information goes along two paths: together with the spinothalamic tract to the optic tubercle along the thin (fibers C) and medium (fibers B) conductors; the second way - together with the conductors of deep sensitivity (fibers A). At the level of the spinal cord, it is not possible to differentiate between sensory animal and sensory vegetative fibers. Undoubtedly, information from the internal organs reaches the cortex, but under normal conditions it is not realized. Experiments with irritation of visceral formations indicate that evoked potentials can be registered in various areas of the cerebral cortex. It is not possible to detect painful conductors in the vagus nerve system. Most likely they go along sympathetic nerves, so it is true that vegetative pains are indicated not by vegetalgia, but by sympathetic.

It is known that sympathetic pain differs from somatic pain in greater diffuseness and affective accompaniment. An explanation for this fact cannot be found in the spread of pain signals along the sympathetic chain, since the sensory pathways pass the sympathetic trunk without interruption. Apparently, the absence in the autonomic afferent systems of receptors and conductors carrying tactile and deep sensitivity, as well as the leading role of the visual hillock as one of the final points of the receipt of sensory information from visceral systems and organs.

It is obvious that the vegetative segmental apparatuses have a certain autonomy and automatism. The latter is determined by the periodic occurrence of an excitatory process in the intramural ganglia on the basis of the current metabolic processes. A convincing example is the activity of the intramural ganglia of the heart during its transplantation, when the heart practically loses all neurogenic extracardiac influences. Autonomy is also determined by the presence of an axon reflex, when excitation is transmitted in the system of one axon, as well as by the mechanism of spinal viscerosomatic reflexes (through the anterior horns of the spinal cord). Recently, data have appeared on nodal reflexes, when the closure is carried out at the level of the prevertebral ganglia. This assumption is based on morphological data on the presence of a two-neuron circuit for sensory autonomic fibers (the first sensory neuron is located in the prevertebral ganglia).

As for the generality and differences in the organization and structure of the sympathetic and parasympathetic divisions, there are no differences between them in the structure of neurons and fibers. The differences relate to the grouping of sympathetic and parasympathetic neurons in the central nervous system (the thoracic spinal cord for the former, the brainstem and sacral spinal cord for the latter) and the location of the ganglia (parasympathetic neurons prevail in the nodes close to the working organ, and sympathetic ones - in the distant ). The latter circumstance leads to the fact that in the sympathetic system the preganglionic fibers are shorter and the postganglionic fibers are longer, and in the parasympathetic system, vice versa. This feature has a significant biological meaning. The effects of sympathetic stimulation are more diffuse and generalized, parasympathetic - less global, more local. The sphere of action of the parasympathetic nervous system is relatively limited and concerns mainly internal organs, at the same time there are no tissues, organs, systems (including the central nervous system), wherever the fibers of the sympathetic nervous system penetrate. The next significant difference is different mediation at the endings of postganglionic fibers (acetylcholine is a mediator of both sympathetic and parasympathetic preganglionic fibers, the effect of which is potentiated by the presence of potassium ions). At the ends of the sympathetic fibers, sympathy is released (a mixture of adrenaline and norepinephrine), which has a local effect, and after absorption into the bloodstream, it is general. The mediator of parasympathetic postganglionic fibers, acetylcholine, causes predominantly local effects and is rapidly destroyed by cholinesterase.

The concept of synaptic transmission is now more complex. First, in the sympathetic and parasympathetic ganglia, not only cholinergic, but also adrenergic (in particular, dopaminergic) and peptidergic (in particular, VCP, a vasoactive intestinal polypeptide) are found. Second, the role of presynaptic formations and postsynaptic receptors in the modulation of various forms of reactions (beta-1-, a-2-, a-1- and a-2-adrenergic receptors) is shown.

The idea of \u200b\u200bthe generalized nature of sympathetic reactions occurring simultaneously in different systems of the body has gained wide popularity and gave rise to the term "sympathetic tone." If we use the most informative method for studying the sympathetic system - measuring the amplitude of general activity in the sympathetic nerves, then this idea should be somewhat supplemented and modified, since different degrees of activity are found in individual sympathetic nerves. This indicates a differentiated regional control of sympathetic activity, i.e., against the background of general generalized activation, certain systems have their own level of activity. Thus, at rest and during exercise, a different level of activity in the skin and muscle sympathetic fibers was established. Within certain systems (skin, muscles), a high parallelism of the activity of sympathetic nerves in various muscles or skin of the feet and hands was noted.

This indicates homogeneous supraspinal control of certain populations of sympathetic neurons. All this speaks of the well-known relativity of the concept of "general sympathetic tone".

Another important method for assessing sympathetic activity is the level of plasma norepinephrine. This is understandable in connection with the release of this mediator in postganglionic sympathetic neurons, its increase during electrical stimulation of the sympathetic nerves, as well as during stressful situations and certain functional loads. Plasma norepinephrine levels vary from person to person, but they are relatively constant in a specific person. In older people, it is slightly higher than in young people. A positive correlation was found between the frequency of volleys in sympathetic muscle nerves and the plasma concentration of noradrenaline in the venous blood. This can be explained by two circumstances:

1. the level of sympathetic activity in the muscles reflects the level of activity in other sympathetic nerves. However, we have already talked about the different activities of the nerves that supply the muscles and skin;
2. muscles make up 40% of the total mass and contain a large number of adrenergic endings, therefore, the release of adrenaline from them will determine the level of plasma norepinephrine concentration.

At that time, a definite relationship between blood pressure and plasma norepinephrine levels cannot be detected. Thus, modern vegetation is constantly taking the path of accurate quantitative estimates instead of general provisions on sympathetic activation.

When considering the anatomy of the segmental vegetative system, it is advisable to take into account the data of embryology. The sympathetic chain is formed as a result of the displacement of neuroblasts from the medullary tube. In the embryonic period, vegetative structures develop mainly from the nerve cushion (crista neuralis),in which there is a certain regionalization; cells of the sympathetic ganglia are formed from elements located along the entire length of the nerve roller, and migrate in three directions: paravertebral, prevertebral and previsceral. Paravertebral clusters of neurons with vertical connections form a sympathetic chain, the right and left chains can have transverse connections at the lower cervical and lumbosacral levels.

Prevertebral migrating cell masses at the level of the abdominal aorta form the prevertebral sympathetic ganglia. The previsceral sympathetic ganglia are found near the pelvic organs or in their wall — the previsceral sympathetic ganglia (referred to as the "minor adrenergic system"). At the later stages of embryogenesis, preganglionic fibers (from spinal cord cells) approach the peripheral autonomic ganglia. Completion of myelination of preganglionic fibers occurs after birth.

The bulk of the intestinal ganglia originate from the "vagal" level of the nerve fold, from where neuroblasts migrate in the ventral direction. The precursors of the intestinal ganglia are involved in the formation of the wall of the anterior part of the alimentary canal. They then migrate caudally along the intestine and form the Meissner and Auerbach plexuses. Parasympathetic Remak's ganglia and some ganglia of the lower intestine are formed from the lumbo-sacral part of the nerve roller.

The vegetative peripheral nodes of the face (ciliary, pterygo-palatine, ear) are also formations of a partly medullary tube, partly a trigeminal node. The data presented allow us to imagine these formations as parts of the central nervous system, carried out to the periphery, - a kind of anterior horns of the autonomic system. Thus, preganglionic fibers are elongated intermediate neurons, well described in the somatic system; therefore, autonomic two-neuron in the peripheral link is only apparent.

This is the general plan of the structure of the autonomic nervous system. Only segmental apparatuses are truly specifically vegetative from a functional and morphological standpoint. In addition to the structural features, slower speed of impulse conduction, mediator differences, the provision on the presence of double innervation of organs by sympathetic and parasympathetic fibers remains important. There are exceptions to this position: only sympathetic fibers are suitable for the adrenal medulla (this is explained by the fact that, in essence, this formation is a reformed sympathetic node); only sympathetic fibers are suitable for the sweat glands, at the end of which, however, acetylcholine is released. According to modern concepts, the vessels also have only sympathetic innervation. At the same time, sympathetic vasoconstrictor fibers are distinguished. The given few exceptions only confirm the rule about the presence of double innervation, and the sympathetic and parasympathetic systems have the opposite effect on the working organ. Expansion and narrowing of blood vessels, increased frequency and deceleration of the heart rate, changes in the lumen of the bronchi, secretion and peristalsis in the gastrointestinal tract - all these changes are determined by the nature of the influence of various parts of the autonomic nervous system. The presence of antagonistic influences, which are the most important mechanism of adaptation of the body to changing environmental conditions, formed the basis for a misconception about the functioning of the vegetative system according to the principle of weights.

In accordance with this, it seemed that an increase in the activity of the sympathetic apparatus should lead to a decrease in the functional capabilities of the parasympathetic division (or, conversely, parasympathetic activation causes a decrease in the activity of the sympathetic apparatus). In fact, a different situation arises. Strengthening the functioning of one department under normal physiological conditions leads to compensatory stress in the apparatus of another department, which returns the functional system to homeostatic indicators. The most important role in these processes is played by both suprasegmental formations and segmental autonomic reflexes. In a state of relative rest, when there are no disturbing influences and there is no active work of any nature, the segmental vegetative system can ensure the existence of the organism by carrying out automated activity. In real life situations, adaptation to changing environmental conditions, adaptive behavior is carried out with a pronounced participation of suprasegmental apparatuses that use the segmental vegetative system as an apparatus for rational adaptation. The study of the functioning of the nervous system provides sufficient justification for the position that specialization is achieved through the loss of autonomy. The existence of vegetative apparatuses only confirms this idea.

The autonomic nervous system is a part of the nervous system that regulates the activity of internal organs, glands of internal and external secretion, blood and lymphatic vessels. A characteristic feature of autonomic innervation at the level of the segmental-peripheral section is the presence of two relatively independent systems - the sympathetic and parasympathetic; it is their coordinated activity that provides fine regulation of the functions of internal organs and metabolism. Each organ has dual autonomic innervation. Joint sympathetic and parasympathetic regulation of a number of functions is reciprocal, that is, an increase in the activity of the sympathetic system inhibits parasympathetic influences opposite in effect. When the muscles that dilate the pupil contract (sympathetic innervation), the muscles that constrict the pupil are simultaneously relaxed (parasympathetic innervation). At the same time, in the regulation of certain other functions, both systems unidirectionally affect the work of internal organs. Parasympathetic innervation is carried out by the nerve centers located in the autonomic nuclei of the brain stem, as well as in the sacral spinal cord. Parasympathetic prenodal fibers end in vegetative nodes located in the wall of the working organ or in the immediate vicinity of it. From the stem vegetative centers in the oculomotor, facial, glossopharyngeal and vagus nerves, there are fibers that provide parasympathetic innervation of the smooth muscles of the eye, lacrimal and salivary glands, as well as blood vessels and internal organs of the chest and abdominal cavities. From the sacral parasympathetic center, the prenodal fibers reach the intramural ganglia, to-rye are located in the pelvic organs, and then, as part of the pelvic internal nerves, innervate the bladder, rectum and genitals. With an increase in the activity of the parasympathetic system, a constriction of the pupil occurs, a slowdown in cardiac activity and a decrease in blood pressure, spasm of the small bronchi, increased intestinal motility and relaxation of the sphincters of the bladder and rectum. At the same time, the antagonism of both systems is relative, rather friendly. Their often counteracting effect on autonomic functions provides homeostasis. The innervation of the glands (sweat and salivary) has certain features. The sweat glands are innervated only by the sympathetic nervous system. The salivary glands receive regulatory fibers from the sympathetic and parasympathetic systems, while the activation of both increases salivary secretion. The difference lies in the quantity and quality of saliva: with an increase in the activity of the sympathetic system, several drops of thick, viscous saliva are released, with the activation of the parasympathetic system, abundant secretion of liquid saliva is noted. The activity of the sympathetic and parasympathetic systems is constantly controlled by the central suprasegmental autonomic formations located in the brain. These include the respiratory and vasomotor centers of the brainstem, the hypothalamus, and the limbic system. These formations ensure the coordinated activity of all internal organs, coordinating the general vegetative reactions of the body as a whole, allowing to maintain the constancy of vital activity in changing environmental conditions . V.N.'s activity from. provides a flexible change in such important functions as metabolism, blood circulation, respiration, body temperature, etc., depending on the activity of emotional and mental processes and the level of physical stress. Under the conditions of an integral organism, each behavioral act as a reaction to environmental influences includes somatic, sympathetic and parasympathetic components. So, with a defensive reaction, an increase in the activity of skeletal muscles, regulated by the somatic nervous system, is accompanied by a reaction from V. of N. from. - the so-called. vegetative "framing". This is manifested by increased cardiac activity (sympathetic reaction), vasodilation of functioning muscles (sympathetic and parasympathetic reaction), narrowing of the vessels of internal organs and skin (sympathetic reaction), increased intestinal motility (parasympathetic reaction). The brain stem contains vital respiratory and vasomotor centers. The nuclei located in the subcortical vegetative center, which is the hypothalamic region, regulate body temperature, the activity of the cardiovascular system, gastrointestinal tract, urination, sexual function, all types of metabolism, endocrine function, sleep, wakefulness. In the posterior parts of the hypothalamus, the nuclei that regulate the sympathetic system are concentrated, in the front, the parasympathetic. Higher autonomic centers (hypothalamus and limbic system), together with the cerebral cortex, not only "determine" the autonomic "profile" of an individual, the level of activity of the sympathetic and parasympathetic systems. The emotional life of a person, his behavior, working capacity, and memory largely depend on them.

Content

To control metabolism, the work of the spinal cord and other internal organs of the body, a sympathetic nervous system is needed, consisting of fibers of nerve tissue. The characteristic section is localized in the organs of the central nervous system, characterized by constant monitoring of the internal environment. Excitation of the sympathetic nervous system provokes dysfunction of individual organs. Therefore, such an abnormal condition needs to be controlled, if necessary, regulated by medication.

What is the sympathetic nervous system

It is a part of the autonomic nervous system that encompasses the upper lumbar and thoracic spinal cord, mesenteric nodes, cells of the sympathetic borderline stem, and the solar plexus. In fact, this part of the nervous system is responsible for the vital activity of cells, maintaining the functionality of the whole organism. In this way, a person is provided with an adequate perception of the world and the body's response to the environment. The sympathetic and parasympathetic divisions work in a complex, are the structural elements of the central nervous system.

Structure

On either side of the spine is a sympathetic trunk, which is formed from two symmetrical rows of nerve nodes. They communicate with each other using special bridges, forming a connection so-called "chain" with an unpaired coccygeal node at the end. It is an important element of the autonomic nervous system, which is characterized by autonomous work. To provide the required physical activity, the design distinguishes the following departments:

cervical of 3 nodes;

• chest, which includes 9-12 nodes;
• the area of \u200b\u200bthe lumbar segment of 2-7 nodes;
• sacral, consisting of 4 nodes and one coccygeal.

From these sections, impulses move to the internal organs, support their physiological functionality. The following structural bindings are distinguished. In the cervical region, the nervous system controls the carotid arteries, in the thoracic region - the pulmonary, cardiac plexuses, and in the peritoneal region - the mesenteric, solar, hypogastric, aortic plexuses. Thanks to postganglionic fibers (ganglia), direct communication with the spinal nerves is carried out.

Functions

The sympathetic system is an integral part of human anatomy, located closer to the spine, and is responsible for the proper functioning of internal organs. It controls the flow of blood through the vessels and arteries, fills their branches with vital oxygen. Among the additional functions of this peripheral structure, doctors distinguish:

increasing the physiological abilities of muscles;

• decrease in the absorption and secretory capacity of the gastrointestinal tract;
• increased sugar, blood cholesterol;
• regulation of metabolic processes, metabolism;
• providing increased strength, frequency and heart rate;
• the arrival of nerve impulses to the fibers of the spinal cord;
• dilated pupils;
• innervation of the lower extremities;
• increased blood pressure;
• release of fatty acids;
• decreased tone of smooth muscle fibers;
• an adrenaline rush in the blood;
• increased sweating;
• excitement of sensitive centers;
• expansion of the bronchi of the respiratory system;
• reduction of saliva production.

Sympathetic and parasympathetic nervous system

The interaction of both structures supports the vital activity of the whole organism, the dysfunction of one of the departments leads to serious diseases of the respiratory, cardiovascular, and musculoskeletal systems. The impact is exerted by means of nerve tissues, consisting of fibers, which provide excitability of impulses, their redirection to internal organs. If one of the diseases prevails, the choice of high quality drugs is made by the doctor.

Anyone should understand the purpose of each department, what functions it provides to maintain health. The table below describes both systems, how they can manifest themselves, what effect they can have on the body as a whole:

Differences between the sympathetic and parasympathetic nervous systems

Sympathetic nerves and parasympathetic fibers can be located in a complex, but at the same time they provide a different effect on the body. Before contacting your doctor for advice, it is shown to find out the differences between the sympathetic and parasympathetic systems in structure, location and functionality, in order to approximately understand the potential focus of pathology:

The sympathetic nerves are located locally, while the parasympathetic fibers are more discrete.

1. The preganglionic fibers are short, small, and parasympathetic, often elongated.
2. The nerve endings are sympathetic - adrenergic, while parasympathetic - cholinergic.
3. The sympathetic system is characterized by white and gray connecting branches, while those are absent in the parasympathetic nervous system.

What diseases are associated with the sympathetic system

With increased excitability of the sympathetic nerves, nervous states develop, which cannot always be eliminated by self-hypnosis. An unpleasant symptomatology reminds of itself already in the primary form of pathology, requires immediate medical attention. The doctor recommends to beware of the following diagnoses, to contact your doctor in time for effective treatment.

The sympathetic and parasympathetic nervous systems are parts of one whole, the name of which is ANS. That is, the autonomic nervous system. Each component has its own objectives and should be considered.

general characteristics

The division into divisions is due to morphological as well as functional characteristics. In human life, the nervous system plays a huge role, performing a lot of functions. The system, it should be noted, is rather complex in its structure and is divided into several subspecies, as well as departments, each of which is assigned certain functions. Interestingly, the sympathetic nervous system was designated as such back in 1732, and at first this term meant the entire autonomic NS. However, later, with the accumulation of experience and knowledge of scientists, it was possible to determine that there is a deeper meaning, and therefore this type was “downgraded” to a subspecies.

Sympathetic NS and its features

She is assigned a large number of important functions for the body. Some of the most significant are:

• Regulation of resource consumption;
• Mobilization of forces in emergency situations;
• Controlling emotions.

If such a need arises, the system can increase the amount of energy expended - so that a person can fully function and continue to carry out his tasks. This is what we mean when we talk about hidden resources or opportunities. The state of the whole organism directly depends on how well the SNS copes with its tasks. But if a person is in an agitated state for too long, this will also not be beneficial. But for this there is another subspecies of the nervous system.

Parasympathetic NS and its features

Accumulation of strength and resources, restoration of strength, rest, relaxation are its main functions. The parasympathetic nervous system is responsible for the normal functioning of a person, and regardless of the surrounding conditions. I must say that both of the above systems complement each other, and only working harmoniously and inseparably. they can provide the body with balance and harmony.

Anatomical features and functions of the SNS

So, the sympathetic NA is characterized by a branched and complex structure. Its central part is located in the spinal cord, and the endings and nerve nodes are connected by the periphery, which, in turn, is formed thanks to sensitive neurons. From them, special processes are formed that extend from the spinal cord, collecting in the paravertebral nodes. In general, the structure is complex, but it is not necessary to delve into its specifics. Better to talk about how broad the functions of the sympathetic nervous system are. It was said that she begins to actively work in extreme, dangerous situations.

At such moments, as you know, adrenaline is produced, which serves as the main substance that enables a person to quickly respond to what is happening around him. By the way, if a person has a pronounced predominance of the sympathetic nervous system, then he usually has an excess of this hormone.

Athletes can be considered an interesting example - for example, watching the game of European players, you can see how many of them start to play much better after they have been scored. That's right, adrenaline is released into the bloodstream, and it turns out what was said just above.

But an excess of this hormone has a negative effect on a person's condition later - he begins to feel tired, tired, there is a great desire to sleep. But if the parasympathetic system prevails, this is also bad. The person becomes too apathetic, overwhelmed. So it is important that the sympathetic and parasympathetic systems interact with each other - this will help maintain balance in the body, as well as wisely spend resources.

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The complex structure of the human body provides for several sublevels of nervous regulation of each organ. So, for the sympathetic nervous system, the mobilization of energy resources is inherent to perform a specific task. The vegetative department controls the work of structures in their functional rest, for example, at the time of sleep. Correct interaction and activity of the autonomic nervous system as a whole is the key to good human health.

Nature wisely distributed the functional responsibilities of the sympathetic and parasympathetic divisions of the autonomic nervous system - according to the location of their nuclei and fibers, as well as their purpose and responsibility. For example, the central neurons of the sympathetic segment are located exclusively in the lateral horns of the spinal cord. In the parasympathetic, they are localized in the trunk of the hemispheres.

Distant, effector neurons in the first case are always located on the periphery - they are present in the paravertebral ganglia. They form various plexuses, the most important of which is the solar one. It is responsible for the innervation of the intra-abdominal organs. Whereas parasympathetic effector neurons are located directly in the organs they innervate. Therefore, the responses to the impulses sent to them from the brain come faster.

Differences can also be observed in functional characteristics. Vigorous human activity requires activation of the heart, blood vessels, lungs - the activity of sympathetic fibers increases. However, in this case, inhibition of digestion processes occurs.

At rest, parasympathetic is responsible for the innervation of the intracavitary organs - digestion, homeostasis, and urination are restored. No wonder, after a hearty lunch, you want to lie down and sleep. The close cooperation of both departments is the unity and indivisibility of the nervous system.

Structural units

The main centers of the vegetative system are localized:

• meseencephalic part - in the structures of the midbrain, from which they depart with a fiber of the oculomotor nerve;
• bulbar segment - in the tissues of the medulla oblongata, which is further represented, both the facial and vagus, glossopharyngeal nerve;
• thoraco-lumbar region - lumbar and thoracic ganglia in the spinal segments;
• the sacral segment is in the sacral region, the parasympathetic nervous system innervates the pelvic organs.

The sympathetic section removes nerve fibers from the brain to the border segment - by the paravertebral ganglia in the region of the spinal cord. It is called the symptomatic trunk, since it contains several nodes, each of which is interconnected with individual organs through the nerve plexuses. The transmission of impulses from nerve fibers to the innervated tissue occurs through synapses - with the help of special biochemical compounds, sympatines.

The parasympathetic division, in addition to the intracranial central nuclei, is represented by:

• preganglionic neurons and fibers - lie within the cranial nerves;
• postanglionic neurons and fibers - pass to innervated structures;
• terminal nodes - located near the intracavitary organs or directly in their tissues.

The peripheral nervous system, represented by two divisions, practically defies conscious control and functions independently, maintaining the constancy of homeostasis.

The essence of interaction

In order for a person to adapt and adapt to any situation - external or internal threat, the sympathetic and parasympathetic parts of the autonomic nervous system must interact closely. However, at the same time they have the opposite effect on the human body.

Parasympathetic is characterized by:

• lower blood pressure;
• reduce breathing rate;
• expand the lumen of blood vessels;
• constrict the pupils;
• adjust the concentration of glucose in the bloodstream;
• improve the digestive process;
• tone up smooth muscles.

Protective reflexes are also in the introduction of parasympathetic activity - sneezing, coughing, retching. For the sympathetic part of the autonomic nervous system, it is inherent to increase the parameters of the cardiovascular system - pulse rate and blood pressure numbers, to enhance metabolism.

The fact that sympathetic department prevails, a person learns from a feeling of fever, tachycardia, restless sleep and fear of death, sweating. If more parasympathetic activity is active, the changes will be different - cold, moist skin, bradycardia, fainting, excessive salivation and shortness of breath. With the balanced functioning of both departments, the activity of the heart, lungs, kidneys, intestines corresponds to the age norm and a person feels healthy.

Functions

Nature has determined that the sympathetic department takes an active part in many important processes of the human body - especially the motor state. It is predominantly assigned the role of mobilizing internal resources in order to overcome various obstacles. For example, it activates the sphincter of the iris, the pupil dilates, and the flow of incoming information increases.

When the sympathetic nervous system is excited, the bronchi expand to increase the supply of oxygen to the tissues, more blood flows to the heart, while at the periphery of the arteries and veins become narrow - the redistribution of nutrients. At the same time, the release of deposited blood from the spleen occurs, as well as the splitting of glycogen - the mobilization of additional energy sources. The digestive and urinary structures will be suppressed - the absorption of nutrients in the intestine slows down, the tissue of the bladder relaxes. All efforts of the body are aimed at maintaining high activity of the muscles.

The parasympathetic effect on cardiac activity will be expressed in the restoration of rhythm and contractions, the normalization of blood regulation - blood pressure corresponds to the parameters familiar to a person. The respiratory system will be corrected - the bronchi narrow, hyperventilation stops, and the concentration of glucose in the bloodstream decreases. At the same time, the motility in the intestinal loops increases - the products are absorbed faster, and the hollow organs are freed from the contents - defecation, urination. Additionally, parasympathetic increases salivary secretion, but reduces sweating.

Violations and pathologies

The structure of the autonomic system as a whole is a complex plexus of nerve fibers that work together to maintain stability within the body. Therefore, even a slight damage to one of the centers will negatively affect the innervation of the internal organs as a whole. For example, with a high tone of the sympathetic nervous system, a huge amount of adrenal hormones constantly enter the blood of people, which provokes surges in blood pressure, tachycardia, sweating, hyperexcitation, and rapid depletion of strength. While lethargy and drowsiness, increased appetite and hypotension will be signs of disruptions in the vegetative department.

Clinical signs of diseases of the peripheral nervous system are directly related to the level at which the nerve fiber was damaged and the causes - inflammation, infection, or injury, tumor process. Typical symptoms of inflammation are tissue edema, pain syndrome, fever, movement disorders in the part of the body that the segment innervates. The specialist must take into account the possibility of irradiation of signs - their distance from the primary focus of the disease. For example, changes in the oculomotor nerve can be expressed in drooping eyelids, increased tear production, difficulty in moving the eyeball.

If sympathetic NS suffers in the pelvic region, which is inherent in children, then enuresis, intestinal obstruction is formed. Or problems with the reproductive system in adults. In case of injuries, the clinical picture will be dominated by tissue damage, bleeding, and subsequently paresis and paralysis.

Treatment principles

Suspicions of disorders of the sympathetic system or the parasympathetic division must be confirmed by an examination by a neurologist, the results of laboratory and instrumental studies.

Only after assessing the general state of human health, identifying the causes of the disease, the specialist will select the optimal therapy regimen. When a tumor is diagnosed, it will be removed surgically or subjected to radiation, chemotherapy. To speed up rehabilitation after injury, the doctor will prescribe physiotherapy procedures, drugs that can accelerate regeneration, as well as means to prevent secondary infection.

If the sympathetic nervous structure suffers from an excess of hormone secretion, the endocrinologist will select medications to change their concentration in the bloodstream. Additionally, decoctions and infusions of medicinal herbs with a calming effect are prescribed - lemon balm, chamomile, as well as mint, valerian. According to individual indications, they resort to the help of antidepressants, anticonvulsants or antipsychotics. The names, doses and duration of treatment are the prerogative of the neuropathologist. Self-medication is absolutely unacceptable.

The spa treatment - mud therapy, hydrotherapy, hirudotherapy, radon baths - has proven itself to be excellent. A complex effect from the inside - rest, proper nutrition, vitamins and outside - healing wraps with herbs, mud, baths with medicinal salt, normalize all parts of the peripheral nervous system.

Prevention

The best treatment for any disease is, of course, prevention. To prevent functional failures in the innervation of one or another organ, experts recommend that people follow the basic principles of a healthy lifestyle:

• give up bad habits - the use of tobacco, alcoholic products;
• get enough sleep - at least 8-9 hours of sleep in a ventilated, darkened, calm room;
• adjust the diet - the predominance of vegetables, various fruits, herbs, cereals;
• compliance with the water regime - intake of at least 1.5–2 liters of purified water, juices, fruit drinks, compotes, so that toxins and toxins are removed from the tissues;
• daily activity - long walks, swimming pool, gym, yoga, Pilates.

A person who carefully monitors his health, visits a doctor for an annual medical examination, the nerves will be calm at any level. Therefore, they know about such problems as sweating, tachycardia, shortness of breath, high blood pressure only by hearsay, from their relatives.