The value of the autonomic nervous system. What is the autonomic nervous system

13.1. GENERAL PROVISIONS

The autonomic nervous system can be seen as a complex of structures that make up the peripheral and central parts of the nervous system, providing regulation of the functions of organs and tissues, aimed at maintaining relative constancy in the body internal environment(homeostasis). In addition, the autonomic nervous system is involved in the implementation of adaptive-trophic influences, as well as various forms of physical and mental activity.

Included in the head and spinal cord the structures of the autonomic nervous system make up its central section, the rest are peripheral. In the central section, it is customary to distinguish suprasegmental and segmental vegetative structures. The suprasegmental ones are areas of the cerebral cortex (mainly located mediobasally), as well as some formations of the diencephalon, primarily the hypothalamus. Segmental structures of the central division of the autonomic nervous system located in the brain stem and spinal cord. in the peripheral nervous system its vegetative part is represented by vegetative nodes, trunks and plexuses, afferent and efferent fibers, as well as vegetative cells and fibers that are part of structures that are usually considered as animal (spinal nodes, nerve trunks, etc.), although in fact they have a mixed character.

Among the suprasegmental vegetative formations, the hypothalamic part of the diencephalon is of particular importance, the function of which is largely controlled by other brain structures, including the cerebral cortex. The hypothalamus ensures the integration of the functions of the animal (somatic) and phylogenetically older autonomic nervous system.

The autonomic nervous system is also known as autonomous in view of its certain, albeit relative, autonomy, or visceral due to the fact that through it the regulation of the functions of internal organs is carried out.

13.2. BACKGROUND

The first information about the structures and functions of autonomic structures is associated with the name of Galen (c. 130-c. 200), since it was he who studied the cranial nerves.

you described nervus vagus and the border trunk, which he called sympathetic. In the book of A. Vesalius (1514-1564) “The Structure of the Human Body”, published in 1543, an image of these formations is given and the ganglia of the sympathetic trunk are described.

In 1732, J. Winslow (Winslow J., 1669-1760) identified three groups of nerves, the branches of which, exerting a friendly influence on each other ("sympathy"), extend to the internal organs. The term "vegetative nervous system" to refer to the nervous structures that regulate the function of internal organs was introduced in 1807 by the German physician I. Reil (Reill I.). French anatomist and physiologist M.F. Bisha (Bicha M.F., 1771-1802) believed that the sympathetic nodes scattered in different parts of the body act independently (autonomously) and from each of them there are branches that connect them together and ensure their influence on the internal organs. In 1800, he was also asked division of the nervous system into vegetative (vegetative) and animal (animal). In 1852, the French physiologist Claude Bernard (Bernard Claude, 1813-1878) proved that irritation of the cervical sympathetic nerve trunk leads to vasodilation, thus describing the vasomotor function of the sympathetic nerves. He also established that an injection of the bottom of the IV ventricle of the brain ("sugar injection") changes the state of carbohydrate metabolism in the body.

AT late XIX in. English physiologist J. Langley (Langley J.N., 1852-1925) introduced the term "autonomic nervous system" while noting that the word "autonomous" undoubtedly indicates a greater degree of independence from the central nervous system than it really is. Based on morphological differences, as well as signs of functional antagonism of individual vegetative structures, J. Langley singled out sympathetic and parasympathetic parts of the autonomic nervous system. He also proved that in the CNS there are centers of the parasympathetic nervous system in the middle and medulla oblongata, as well as in the sacral segments of the spinal cord. In 1898, J. Langley established in the peripheral part of the autonomic nervous system (on the way from the CNS structures to the working organ) the presence of synaptic apparatuses located in the autonomic nodes, in which efferent nerve impulses are switched from neuron to neuron. He noted that the peripheral part of the autonomic nervous system contains preganglionic and postganglionic nerve fibers and quite accurately described the general plan of the structure of the autonomic (vegetative) nervous system.

In 1901, T. Elliott (Elliott T.) suggested the chemical transmission of nerve impulses in the vegetative nodes, and in 1921, in the process of experimental studies, this position was confirmed by the Austrian physiologist O. Levi (Loewi O., 1873-1961) and , thus laid the foundation for the doctrine of mediators (neurotransmitters). In 1930 an American physiologist W. Cannon(Cannon W., 1871-1945), studying the role of the humoral factor and vegetative mechanisms in maintaining the relative constancy of the internal environment of the body, introduced the term"homeostasis" and in 1939 he established that if the movement of nerve impulses is interrupted in a functional row of neurons in one of the links, then the resulting total or partial denervation of subsequent links in the chain causes an increase in the sensitivity of all receptors located in them to an excitatory or inhibitory effect

chemicals (including medicines) with properties similar to the corresponding mediators (Cannon-Rosenbluth law).

A significant role in the knowledge of the functions of the autonomic nervous system of the German physiologist E. Hering (Hering E., 1834-1918), who discovered carotid sinus reflexes, and the domestic physiologist L.A. Orbeli (1882-1958), who created the theory of the adaptive-trophic influence of the sympathetic nervous system. Many clinical neurologists, including our compatriots M.I. Astvatsaturov, G.I. Markelov, N.M. Itsenko, I.I. Rusetsky, A.M. Grinshtein, N.I. Grashchenkov, N.S. Chetverikov, A.M. Wayne.

13.3. STRUCTURE AND FUNCTIONS OF THE AUTONOMIC NERVOUS SYSTEM

Taking into account the structural features and functions of the segmental division of the autonomic nervous system, it is distinguished mainly sympathetic and parasympathetic divisions (Fig. 13.1). The first of them provides mainly catabolic processes, the second - anabolic. The composition of the sympathetic and parasympathetic divisions of the autonomic nervous system includes both afferent and efferent, as well as intercalary structures. Already on the basis of these data, it is possible to outline the scheme for constructing a vegetative reflex.

13.3.1. Autonomic reflex arc (principles of construction)

The presence of the afferent and efferent sections of the autonomic nervous system, as well as associative (intercalary) formations between them, ensures the formation of autonomic reflexes, the arcs of which are closed at the spinal or cerebral level. Them afferent link represented by receptors (mainly chemoreceptors) located in almost all organs and tissues, as well as vegetative fibers extending from them - dendrites of the first sensitive vegetative neurons, which ensure the conduction of vegetative impulses in a centripetal direction to the bodies of these neurons located in the spinal brain nodes or their analogues, which are part of the cranial nerves. Further, vegetative impulses, following the axons of the first sensory neurons through the posterior spinal roots, enter the spinal cord or brain and end at the intercalary (associative) neurons that are part of the segmental vegetative centers spinal cord or brain stem. association neurons, in turn, they have numerous vertical and horizontal intersegmental connections and are under the control of suprasegmental vegetative structures.

Efferent section of the arc of autonomic reflexes consists of preganglionic fibers, which are axons of cells of autonomic centers (nuclei) of the segmental part of the central nervous system (brain stem, spinal

Rice. 13.1.autonomic nervous system.

1 - cerebral cortex; 2 - hypothalamus; 3 - ciliary knot; 4 - pterygopalatine node; 5 - submandibular and sublingual nodes; 6 - ear knot; 7 - upper cervical sympathetic node; 8 - large splanchnic nerve; 9 - internal node; 10 - celiac plexus; 11 - celiac nodes; 12 - small internal

nerve; 13, 14 - superior mesenteric plexus; 15 - lower mesenteric plexus; 16 - aortic plexus; 17 - pelvic nerve; 18 - hypogastric plexus; 19 - ciliary muscle, 20 - pupil sphincter; 21 - pupil dilator; 22 - lacrimal gland; 23 - glands of the mucous membrane of the nasal cavity; 24 - submandibular gland; 25 - sublingual gland; 26 - parotid gland; 27 - heart; 28 - thyroid gland; 29 - larynx; 30 - muscles of the trachea and bronchi; 31 - lung; 32 - stomach; 33 - liver; 34 - pancreas; 35 - adrenal gland; 36 - spleen; 37 - kidney; 38 - large intestine; 39 - small intestine; 40 - bladder detrusor; 41 - sphincter of the bladder; 42 - gonads; 43 - genitals.

brain), which leave the brain as part of the anterior spinal roots and reach certain peripheral autonomic ganglia. Here, vegetative impulses are switched to neurons whose bodies are located in the ganglia and then along the postganglionic fibers, which are the axons of these neurons, they follow to the innervated organs and tissues.

13.3.2. Afferent structures of the autonomic nervous system

The morphological substrate of the afferent part of the peripheral part of the autonomic nervous system does not have any fundamental differences from the afferent part of the peripheral part of the animal nervous system. The bodies of the first sensory vegetative neurons are located in the same spinal nodes or nodes of cranial nerves that are their analogues, which also contain the first neurons of animal sensory pathways. Consequently, these nodes are animal-vegetative (somato-vegetative) formations, which can be considered as one of the facts indicating the fuzzy outline of the boundaries between the animal and autonomic structures of the nervous system.

The bodies of the second and subsequent sensitive autonomic neurons are located in the spinal cord or in the brain stem, their processes have contacts with many structures of the central nervous system, in particular with the nuclei of the diencephalon, primarily the thalamus and hypothalamus, as well as with other parts of the brain that are part of the limbic- reticular complex. In the afferent link of the autonomic nervous system, an abundance of receptors (interoreceptors, visceroreceptors) located in almost all organs and tissues can be noted.

13.3.3. Efferent structures of the autonomic nervous system

If the structure of the afferent part of the autonomic and animal parts of the nervous system can be very similar, then the efferent link of the autonomic nervous system is characterized by very significant morphological features, while they are not identical in its parasympathetic and sympathetic parts.

13.3.3.1. The structure of the efferent link of the parasympathetic division of the autonomic nervous system

The central division of the parasympathetic nervous system is divided into three parts: mesencephalic, bulbar and sacral.

mesencephalic part are paired parasympathetic nuclei of Yakubovich-Westphal-Edinger, related to the system of oculomotor nerves. peripheral part mesencephalic part of the peripheral nervous system consists of axons of this nucleus, constituting the parasympathetic portion of the oculomotor nerve, which penetrates into the cavity of the orbit through the superior orbital fissure, while the preganglionic parasympathetic fibers included in it reach located in the fiber of the eye socket ciliary knot (ganglion ciliare), in which the switching of nerve impulses from neuron to neuron occurs. The postganglionic parasympathetic fibers emerging from it are involved in the formation of short ciliary nerves (nn. ciliares breves) and end in the smooth muscles innervated by them: in the muscle that narrows the pupil (m. sphincter pupille) and in the ciliary muscle (m. ciliaris ), the reduction of which provides accommodation for the lens.

To bulbar part The parasympathetic nervous system includes three pairs of parasympathetic nuclei - the upper salivary, lower salivary and dorsal. The axons of the cells of these nuclei make up the parasympathetic portions, respectively, of the intermediate nerve of Wrisberg (going part of the path as part of the facial nerve), glossopharyngeal and vagus nerves. These parasympathetic structures of these cranial nerves consist of preganglionic fibers that end in vegetative nodes. In the system of intermediate and glossopharyngeal nerves this is pterygopalatine (g. pterygopalatum), ear (g. oticum), sublingual and submandibular nodes(g. sublingualis and g. submandibularis). Outgoing from these parasympathetic nodes postganglionic nervous fibers reach innervated by them lacrimal gland, salivary glands and mucous glands of the nose and mouth.

The axons of the dorsal parasympathetic nucleus of the vagus nerve leave the medulla oblongata in its composition, leaving, thus, cranial cavity through the jugular foramen. After that, they end in numerous autonomic nodes of the vagus nerve system. Already at the level jugular foramen where are located two nodes of this nerve (upper and lower), part of the preganglionic fibers ends in them. Later, postganglionic fibers depart from the upper node, forming meningeal branches, involved in the innervation of the dura mater, and ear branch; departs from the inferior node of the vagus nerve pharyngeal branch. In the future, others are separated from the trunk of the vagus nerve preganglionic fibers forming the cardiac depressive nerve and partly the recurrent nerve of the larynx; branch off the vagus nerve in the chest cavity tracheal, bronchial and esophageal branches, in the abdominal cavity - anterior and posterior stomach and stomach. The preganglionic fibers innervating the internal organs end in the parasympathetic paraorganic and intraorganic (intramural) nodes,

located in the walls of internal organs or in their immediate vicinity. Postganglionic fibers from these nodes provide parasympathetic innervation of the thoracic and abdominal organs. The excitatory parasympathetic effect on these organs affects the

leniya heart rate, narrowing of the lumen of the bronchi, increased peristalsis of the esophagus, stomach and intestines, increased secretion of gastric and duodenal juice, etc.

sacral part the parasympathetic nervous system are accumulations of parasympathetic cells in the gray matter of segments S II -S IV of the spinal cord. The axons of these cells leave the spinal cord as part of the anterior roots, then pass along the anterior branches of the sacral spinal nerves and separate from them in the form pudendal nerves (nn. pudendi), who take part in the formation lower hypogastric plexus and run out in intraorgan parasympathetic nodes of the small pelvis. The organs in which these nodes are located are innervated by postganglionic fibers extending from them.

13.3.3.2. The structure of the efferent link of the sympathetic division of the autonomic nervous system

The central part of the sympathetic autonomic nervous system is represented by cells of the lateral horns of the spinal cord at the level from the VIII cervical to III-IV lumbar segments. These vegetative cells together form the spinal sympathetic center, or columna intermedia (autonomica).

Components of the spinal sympathetic center Jacobson cells (small, multipolar) associated with higher vegetative centers, included in the system of the limbic-reticular complex, which, in turn, have connections with the cerebral cortex and are under the influence of impulses emanating from the cortex. Axons of sympathetic Jacobson cells exit the spinal cord as part of the anterior spinal roots. Later, having passed through the intervertebral foramen as part of the spinal nerves, they fall into their white connecting branches (rami communicantes albi). Each white connecting branch enters one of the paravertebral (paravertebral) nodes that make up the border sympathetic trunk. Here, part of the fibers of the white connecting branch ends and forms synaptic contacts with sympathetic cells of these nodes, the other part of the fibers passes through the paravertebral node in transit and reaches the cells of other nodes of the border sympathetic trunk or prevertebral (prevertebral) sympathetic nodes.

The nodes of the sympathetic trunk (paravertebral nodes) are located in a chain on both sides of the spine, internodal connecting branches pass between them. (rami communicantes interganglionares), and thus form border sympathetic trunks (trunci sympathici dexter et sinister), consisting of a chain of 17-22 sympathetic nodes, between which there are also transverse connections (tracti transversalis). The border sympathetic trunks extend from the base of the skull to the coccyx and have 4 sections: cervical, thoracic, lumbar and sacral.

Part of the axons devoid of myelin sheath of cells located in the nodes of the border sympathetic trunk forms gray connecting branches (rami communicantes grisei) and then enters the structures of the peripheral nervous system: in the anterior branch spinal nerve, nerve plexus and peripheral nerves approaches various tissues, providing their sympathetic innervation. This part performs, in particular,

sympathetic innervation of the pilomotor muscles, as well as the sweat and sebaceous glands. Another part of the postganglionic fibers of the sympathetic trunk forms plexuses that spread along the blood vessels. The third part of the postganglionic fibers, together with the preganglionic fibers that have passed by the ganglia of the sympathetic trunk, form sympathetic nerves, heading mainly to the internal organs. Along the way, the preganglionic fibers included in their composition end in the prevertebral sympathetic nodes, from which the postganglionic fibers also depart, which are involved in the innervation of organs and tissues. Cervical sympathetic trunk:

1) cervical sympathetic nodes - upper, middle and lower. Upper cervical knot (gangl. cervicale superius) located near the occipital bone at the level of the first three cervical vertebrae along the dorsomedial surface of the internal carotid artery. Middle neck knot (gangl. cervicale medium) unstable, located at the level of the IV-VI cervical vertebrae, in front of the subclavian artery, medial to the I rib. Lower cervical knot (gangl. cervicale inferior) in 75-80% of people it merges with the first (less often with the second) thoracic node, with the formation of a large cervicothoracic node (gangl. cervicothoracicum), or the so-called stellate knot (gangl. stellatum).

There are no lateral horns and vegetative cells at the cervical level of the spinal cord; therefore, the preganglionic fibers leading to the cervical ganglia are axons of sympathetic cells, the bodies of which are located in the lateral horns of the four or five upper thoracic segments, they enter the cervicothoracic ( stellate) node. Some of these axons end at this node, and the nerve impulses traveling along them are switched here to the next neuron. The other part passes the node of the sympathetic trunk in transit and the impulses passing through them switch to the next sympathetic neuron in the upper middle or upper cervical sympathetic node.

The postganglionic fibers extending from the cervical nodes of the sympathetic trunk give off branches that provide sympathetic innervation of the organs and tissues of the neck and head. Postganglionic fibers originating from the superior cervical ganglion form the plexus of the carotid arteries, controlling tone vascular wall these arteries and their branches, as well as provide sympathetic innervation of the sweat glands, the smooth muscle that dilates the pupil (m. dilatator pupillae), the deep plate of the muscle that lifts the upper eyelid (lamina profunda m. levator palpebrae superioris), and the orbital muscle (m. orbitalis). Branches involved in innervation also depart from the plexus of the carotid arteries. lacrimal and salivary glands, hair follicles, thyroid artery, as well as innervating the larynx, pharynx, involved in the formation of the upper cardiac nerve, which is part of the cardiac plexus.

From the axons of neurons located in the middle cervical sympathetic ganglion, a middle cardiac nerve involved in the formation of the cardiac plexus.

Postganglionic fibers extending from the lower cervical sympathetic node or formed in connection with its fusion with the upper thoracic node of the cervicothoracic, or stellate, node, form the sympathetic plexus of the vertebral artery, also known as vertebral nerve. This plexus surrounds vertebral artery, together with it passes through the bone canal formed by holes in the transverse processes of the C VI -C II vertebrae and enters the cranial cavity through the large occipital foramen.

2) The thoracic part of the paravertebral sympathetic trunk consists of 9-12 nodes. Each of them has a white connecting branch. Gray connecting branches go to all intercostal nerves. Visceral branches from the first four nodes are directed to the heart, lungs, pleura, where, together with the branches of the vagus nerve, they form the corresponding plexuses. Branches from 6-9 nodes form great celiac nerve, which passes into the abdominal cavity and enters into abdominal knot, part of the celiac (solar) plexus complex (Plexus coeliacus). Branches of the last 2-3 nodes of the sympathetic trunk form small celiac nerve, part of the branches of which branches in the adrenal and renal plexuses.

3) The lumbar part of the paravertebral sympathetic trunk consists of 2-7 nodes. White connecting branches are suitable only for the first 2-3 nodes. Gray connecting branches depart from all lumbar sympathetic nodes to the spinal nerves, and visceral trunks form the abdominal aortic plexus.

4) sacral part The paravertebral sympathetic trunk consists of four pairs of sacral and one pair of coccygeal ganglia. All these ganglia are connected to the sacral spinal nerves, give off branches to the organs and neurovascular plexuses of the small pelvis.

Prevertebral sympathetic nodes are variable in shape and size. Their clusters and associated vegetative fibers form plexuses. Topographically, the prevertebral plexuses of the neck, thoracic, abdominal and pelvic cavities are distinguished. In the chest cavity, the largest are the cardiac, and in the abdominal cavity - the celiac (solar), aortic, mesenteric, hypogastric plexuses.

Of the peripheral nerves, the median and sciatic nerves, as well as the tibial nerve, are the richest in sympathetic fibers. Their defeat, usually traumatic, more often than the defeat of other peripheral nerves, causes the occurrence causalgia. Pain in causalgia is burning, extremely painful, difficult to localize, tending to spread far beyond the zone innervated by the affected nerve, in which, by the way, pronounced hyperpathy is usually noted. Patients with causalgia are characterized by some relief of the condition and a decrease in pain when the innervation zone is moistened (a symptom of a wet rag).

Sympathetic innervation of the tissues of the trunk and limbs, as well as internal organs, is segmental in nature, at the same time, the zones of the segments do not correspond to the metameres characteristic of somatic spinal innervation. Sympathetic segments (cells of the lateral horns of the spinal cord that make up the spinal sympathetic center) from C VIII to Th III provide sympathetic innervation to the tissues of the head and neck, segments Th IV - Th VII - tissues of the shoulder girdle and arm, segments Th VIII Th IX - torso; the lowest segments, which include lateral horns, Th X -Th III, provide sympathetic innervation to the organs of the pelvic girdle and legs.

Sympathetic innervation of the internal organs is provided by autonomic fibers associated with certain segments of the spinal cord. Pain arising from damage to internal organs can radiate to the zones of the dermatomes corresponding to these segments. (Zakharyin-Ged zones) . Such reflected pain, or hyperesthesia, occurs as a viscerosensory reflex (Fig. 13.2).

Rice. 13.2.Zones of reflected pain (Zakharyin-Ged zones) on the trunk in diseases of the internal organs - viscerosensory reflex.

Vegetative cells are small in size, their fibers are non-fleshy or with a very thin myelin sheath, they belong to groups B and C. In this regard, the speed of passage of nerve impulses in vegetative fibers is relatively small.

13.3.4. Metasympathetic division of the autonomic nervous system

In addition to the parasympathetic and sympathetic divisions, physiologists distinguish the metasympathetic division of the autonomic nervous system. This term refers to a complex of microganglionic formations located in the walls of internal organs that have motor activity (heart, intestines, ureters, etc.) and ensure their autonomy. The function of the nerve nodes is to transmit central (sympathetic, parasympathetic) influences to the tissues, and, in addition, they provide the integration of information coming through local reflex arcs. Metasympathetic structures are independent formations capable of functioning with complete decentralization. Several (5-7) of the neighboring nodes related to them are combined into a single functional module, the main units of which are oscillator cells that ensure the autonomy of the system, interneurons, motoneurons, and sensitive cells. Separate functional modules constitute a plexus, due to which, for example, a peristaltic wave is organized in the intestine.

The functions of the metasympathetic division of the autonomic nervous system do not directly depend on the activity of the sympathetic or parasympathetic

nervous systems, but can be modified under their influence. So, for example, activation of parasympathetic influence enhances intestinal motility, and sympathetic - weakens it.

13.3.5. suprasegmental vegetative structures

Strictly speaking, irritation of any part of the brain is accompanied by some kind of vegetative response, but in its supratentorially located structures there are no compact territories that could be attributed to specialized vegetative formations. However, there are suprasegmental vegetative structures of the large and diencephalon, which have the most significant, primarily integrative, effect on the state of autonomic innervation of organs and tissues.

These structures include the limbic-reticular complex, primarily the hypothalamus, in which it is customary to distinguish between the anterior - trophotropic and back - ergotropic departments. Structures of the limbic-reticular complex have numerous direct and feedback connections with the new cortex (neocortex) of the cerebral hemispheres, which controls and to some extent corrects their functional state.

Hypothalamus and other parts of the limbic-reticular complex have a global regulatory effect on the segmental divisions of the autonomic nervous system, create a relative balance between the activity of sympathetic and parasympathetic structures, aimed at maintaining a state of homeostasis in the body. In addition, the hypothalamic part of the brain, the amygdala complex, the old and ancient cortex of the mediobasal parts of the cerebral hemispheres, the hippocampal gyrus and other parts of the limbic-reticular complex carry out integration between the vegetative structures, the endocrine system and the emotional sphere, influence the formation of motivations, emotions, memory, behavior.

Pathology of suprasegmental formations can lead to multisystem reactions, in which autonomic disorders are only one of the components of a complex clinical picture.

13.3.6. Mediators and their influence on the state of vegetative structures

The conduction of impulses through synaptic apparatuses in both the central and peripheral nervous systems is carried out due to mediators, or neurotransmitters. In the central nervous system, mediators are numerous and their nature has not been studied in all synaptic connections. Better studied mediators of peripheral nervous structures, in particular those related to the autonomic nervous system. It should also be noted that in the afferent (centripetal, sensory) part of the peripheral nervous system, which consists mainly of pseudo-unipolar cells with their processes, there are no synaptic apparatuses. In the efferent structures (Table 13.1) of the animal (somatic) part of the peripheral nervous system, there are only nervous

Scheme 13.1.Sympathetic apparatus and mediators of the peripheral nervous system CNS - central nervous system; PNS - peripheral nervous system; PS - parasympathetic structures of the CNS; C - sympathetic structures of the central nervous system; a - somatic motor fiber; b - preganglionic vegetative fibers; c - postganglionic vegetative fibers; CIRCLE - synaptic apparatuses; mediators: AH - acetylcholine; NA - norepinephrine.

muscle synapses. The mediator that ensures the conduction of nerve impulses through these synapses is acetylcholine-H (ACh-H), synthesized in peripheral motor neurons located in the structures of the central nervous system, and from there along their axons with axotok into synaptic vesicles located near the presynaptic membrane.

The efferent peripheral part of the autonomic nervous system consists of preganglionic fibers leaving the CNS (brain stem, spinal cord), as well as autonomic ganglia, in which impulses are switched from preganglionic fibers to cells located in the ganglia through the synaptic apparatus. Subsequently, the impulses along the axons (postganglionic fibers) leaving these cells reach the synapse, which ensures the switching of the impulse from these fibers to the innervated tissue.

In this way, all vegetative impulses on the way from the central nervous system to the innervated tissue pass through the synaptic apparatus twice. The first of the synapses is located in the parasympathetic or sympathetic ganglion, the switching of the impulse here in both cases is provided by the same mediator as in the animal neuromuscular synapse, acetylcholine-H (AH-H). The second, parasympathetic and sympathetic, synapses, in which impulses switch from the postganglionic fiber to the innervated structure, are not identical in terms of the emitted mediator. For the parasympathetic division, it is acetylcholine-M (AX-M), for the sympathetic division, it is mainly norepinephrine (NA). This is of significant importance, since with the help of certain drugs it is possible to influence the conduction of nerve impulses in the zone of their passage through the synapse. These drugs include H- and M-cholinomimetics and H- and M-anticholinergics, as well as adrenomimetics and adrenoblockers. When prescribing these drugs, it is necessary to take into account their effect on synaptic structures and predict what response to the administration of each of them should be expected.

The action of a pharmaceutical preparation may affect the function of synapses belonging to different parts of the nervous system, if neurotransmission in them is provided by an identical or similar chemical mediator. Thus, the introduction of ganglioblockers, which are N-anticholinergics, has a blocking effect on the conduction of impulses from the preganglionic fiber to the cell located in the ganglion in both sympathetic and parasympathetic ganglia, and can also suppress the conduction of nerve impulses through the neuromuscular synapses of the animal part of the peripheral nervous system. .

In some cases, it is also possible to influence the conduction of impulses through the synapse by means that affect the conduction of synaptic apparatuses in different ways. So, the cholinomimetic effect is exerted not only by the use of cholinomimetics, in particular acetylcholine, which, by the way, quickly decomposes and therefore is rarely used in clinical practice, but also anticholinesterase drugs from the group of cholinesterase inhibitors (proserin, galanthamine, kalemin, etc.), which leads to protection against rapid destruction of ACh molecules entering the synaptic cleft.

The structures of the autonomic nervous system are characterized by the ability to actively respond to many chemical and humoral stimuli. This circumstance determines the lability of vegetative functions at the slightest change in the chemical composition of tissues, in particular blood, under the influence of changes in endogenous and exogenous influences. It also allows you to actively influence the vegetative balance by introducing certain pharmacological agents into the body that improve or block the conduction of vegetative impulses through the synaptic apparatus.

The autonomic nervous system affects the viability of the body (Table 13.1). It regulates the state of the cardiovascular, respiratory, digestive, genitourinary and endocrine systems, fluid media, and smooth muscles. At the same time, the vegetative system performs an adaptive-trophic function, regulates the energy resources of the body, providing thus all types of physical and mental activity, preparing organs and tissues, including nervous tissue and striated muscles, for the optimal level of their activity and the successful performance of their inherent functions.

Table 13.1.Functions of the sympathetic and parasympathetic divisions of the autonomic nervous system

The end of the table. 13-1

* For most sweat glands, some vessels and skeletal muscles, acetylcholine is the sympathetic mediator. The adrenal medulla is innervated by cholinergic sympathetic neurons.

During a period of danger, hard work, the autonomic nervous system is designed to meet the increasing energy needs of the body and does this by increasing the activity of metabolic processes, increasing pulmonary ventilation, transferring the cardiovascular and respiratory systems to a more intense mode, changing hormonal balance, etc.

13.3.7. Study of autonomic functions

Information about autonomic disorders and their localization can help resolve the issue of the nature and location of the pathological process. Sometimes the identification of signs is of particular importance. autonomic imbalance.

Changes in the functions of the hypothalamus and other suprasegmental structures of the autonomic nervous system lead to generalized autonomic disorders. The defeat of the autonomic nuclei in the brain stem and spinal cord, as well as the peripheral parts of the autonomic nervous system, is usually accompanied by the development of segmental autonomic disorders in a more or less limited part of the body.

When examining the autonomic nervous system, attention should be paid to the patient's physique, the condition of his skin (hyperemia, pallor, sweating, greasiness, hyperkeratosis, etc.), its appendages (baldness, graying; brittleness, dullness, thickening, deformation of the nails); the severity of the subcutaneous fat layer, its distribution; the state of the pupils (deformation, diameter); tearing; salivation; the function of the pelvic organs (urgent urge to urinate, urinary incontinence, urinary retention, diarrhea, constipation). It is necessary to get an idea about the character of the patient, his prevailing mood, well-being, performance, degree of emotionality, ability to adapt to changes in external temperature.

tours. It is necessary to obtain information about the state of the patient's somatic status (frequency, lability, pulse rate, blood pressure, headache, its nature, history of migraine attacks, functions of the respiratory, digestive and other systems), the state of the endocrine system, thermometry results, laboratory parameters . Pay attention to the presence of allergic manifestations in the patient (urticaria, bronchial asthma, angioedema, essential itching, etc.), angiotrophoneurosis, acroangiopathy, sympathalgia, manifestations of "marine" sickness when using transport, "bear" disease.

A neurological examination may reveal anisocoria, dilation or narrowing of the pupils that do not correspond to the available illumination, a violation of the reaction of the pupils to light, convergence, accommodation, total tendon hyperreflexia with a possible expansion of the reflexogenic zones, a general motor reaction, changes in local and reflex dermographism.

Local dermographism It is caused by slight stroke irritation of the skin with a blunt object, for example, the handle of a neurological hammer, the rounded end of a glass rod. Normally, with mild skin irritation, a white stripe appears on it after a few seconds. If the skin irritation is more intense, the resulting strip on the skin is red. In the first case, local dermographism is white, in the second case, local dermographism is red.

If both weak and more intense skin irritation causes the appearance of local white dermographism, we can talk about increased skin vascular tone. If, even with the minimum strength of dashed skin irritations, local red dermographism occurs, and white cannot be obtained, then this indicates low tone skin vessels, primarily precapillaries and capillaries. With a pronounced decrease in their tone, dashed skin irritation not only leads to the appearance of local red dermographism, but also to the penetration of plasma through the walls of blood vessels. Then edematous, or urticarial, or elevated dermographism may occur. (dermographismus elevatus).

Reflex, or pain, dermographism caused by streak irritation of the skin with the tip of a needle or pin. Its reflex arc closes in the segmental apparatus of the spinal cord. In response to pain irritation, a red strip 1-2 mm wide with narrow white edges appears on the skin, which lasts for several minutes.

If the spinal cord is damaged, then in areas of the skin, the vegetative innervation of which should be provided by the affected segments, and in the lower parts of the body, reflex dermographism is absent. This circumstance can help clarify the upper boundary of the pathological focus in the spinal cord. Reflex dermographism disappears in the areas innervated by the affected structures of the peripheral nervous system.

A certain topico-diagnostic value may also have a condition pilomotor (muscle-hair) reflex. It can be caused by pain or cold irritation of the skin in the area of ​​the trapezius muscle (upper pilomotor reflex) or in the gluteal region (lower pilomotor reflex). The response in this case is the occurrence on the corresponding half of the body of a common pilomotor reaction in the form of "goose bumps". The speed and intensity of the reaction indicates the degree

excitability of the sympathetic division of the autonomic nervous system. The arc of the pilomotor reflex closes in the lateral horns of the spinal cord. In transverse lesions of the spinal cord, causing the upper pilomotor reflex, it can be noted that the pilomotor reaction is observed not below the level of the dermatome corresponding to the upper pole of the pathological focus. When the lower pilomotor reflex is evoked, goosebumps occur in the lower body, spreading upward to the lower pole of the pathological focus in the spinal cord.

It should be borne in mind that the results of the study of reflex dermographism and pilomotor reflexes provide only indicative information about the topic of the pathological focus in the spinal cord. Clarification of the localization of the pathological focus may necessitate a more complete neurological examination and often additional examination methods (myelography, MRI scanning).

Certain value for topical diagnostics can have identification of local violations of sweating. For this, iodine-starch is sometimes used. Minor test. The patient's body is lubricated with a solution of iodine in castor oil and alcohol (iodi puri 16.0; olei risini 100.0; spiriti aetylici 900.0). After the skin dries, it is powdered with starch. Then one of the methods that usually cause increased sweating is applied, while the sweaty areas of the skin darken, since the sweat that has come out promotes the reaction of starch with iodine. To provoke sweating, three indicators are used that affect different parts of the autonomic nervous system - various links in the efferent part of the arc of the sweating reflex. Taking 1 g of aspirin causes increased sweating, causing excitation of the sweat center at the level of the hypothalamus. Warming the patient in a light bath mainly affects the spinal sweating centers. Subcutaneous administration of 1 ml of a 1% solution of pilocarpine provokes sweating by stimulating the peripheral endings of the postganglionic autonomic fibers located in the sweat glands themselves.

To determine the degree of excitability of the neuromuscular synaptic apparatus in the heart, orthostatic and clinostatic tests can be performed. Orthostatic reflex occurs when the subject moves from a horizontal to a vertical position. Before the test and within the first minute after the patient's transition to a vertical position, his pulse is measured. Normal - increased heart rate by 10-12 beats per minute. clinostatic test checked when the patient moves from a vertical to a horizontal position. The pulse is also measured before the test and during the first minute after the patient takes a horizontal position. Normally, there is a slowing of the pulse by 10-12 beats per minute.

Lewis test (triad) - a complex of consistently developing vascular reactions for intradermal administration of two drops of acidified 0.01% histamine solution. The following reactions normally occur at the injection site: 1) a red dot (limited erythema) occurs due to local expansion of capillaries; 2) soon it is on top of a white papule (blister), resulting from an increase in the permeability of skin vessels; 3) skin hyperemia develops around the papule due to the expansion of arterioles. The spread of erythema beyond the papule may be absent in case of skin denervation, while during the first few days after a break in the peripheral nerve, it may be intact and disappear with time.

phenomenon in the nerve degenerative changes. The outer red ring surrounding the papule is usually absent in Riley-Day syndrome (familial dysautonomia). The test can also be used to determine vascular permeability, to identify autonomic asymmetries. It was described by the English cardiologist Th. Lewis (1871-1945).

During the clinical examination of patients, other methods of studying the autonomic nervous system can be used, including the study of skin temperature, skin sensitivity to ultraviolet radiation, skin hydrophilicity, skin pharmacological tests with drugs such as adrenaline, acetylcholine and some other vegetotropic agents, the study of electrocutaneous resistance, Dagnini-Ashner's ocular reflex, capillaroscopy, plethysmography, autonomic plexus reflexes (cervical, epigastric), etc. The methodology for their implementation is described in special and reference manuals.

The study of the state of autonomic functions can provide important information about the presence of a functional or organic lesion of the nervous system in a patient, often contributing to the solution of the issue of topical and nosological diagnosis.

Identification of vegetative asymmetries that go beyond the limits of physiological fluctuations can be considered as a sign of diencephalic pathology. Local changes in autonomic innervation can contribute to the topical diagnosis of some diseases of the spinal cord and peripheral nervous system. Soreness and vegetative disorders in the Zakharyin-Ged zones, which are of a reflected nature, may indicate the pathology of one or another internal organ. Signs of increased excitability of the autonomic nervous system, autonomic lability can be an objective confirmation of the patient's neurosis or neurosis-like condition. Their identification sometimes plays a very important role in the professional selection of people for work in certain specialties.

The results of studying the state of the autonomic nervous system to some extent allow us to judge the mental status of a person, primarily his emotional sphere. Such research is at the heart of the discipline that combines physiology and psychology and is known as psychophysiology, confirming the relationship between mental activity and the state of the autonomic nervous system.

13.3.8. Some clinical phenomena depending on the state of the central and peripheral structures of the autonomic nervous system

The state of the autonomic nervous system determines the functions of all organs and tissues and, consequently, the cardiovascular, respiratory, genitourinary systems, digestive tract, and sensory organs. It also affects the functionality of the musculoskeletal system, regulates metabolic processes, ensuring the relative constancy of the internal environment of the body, its viability. Irritation or inhibition of the functions of individual vegetative structures leads to vegetative

imbalance, which in one way or another affects the state of a person, his health, his quality of life. In this regard, it is worth emphasizing the exceptional diversity clinical manifestations caused by autonomic dysfunction, and to pay attention to the fact that representatives of almost all clinical disciplines are concerned about the problems arising in connection with this.

Further, we have the opportunity to dwell only on some clinical phenomena that depend on the state of the autonomic nervous system, which a neurologist has to deal with in everyday work (see also chapters 22, 30, 31).

13.3.9. Acute autonomic dysfunction, manifested by the extinction of autonomic reactions

Vegetative imbalance, as a rule, is accompanied by clinical manifestations, the nature of which depends on its characteristics. Acute vegetative dysfunction (pandysautonomy) due to inhibition of vegetative functions is caused by an acute violation of vegetative regulation, manifested totally, in all tissues and organs. During this multisystemic insufficiency, which is usually associated with immune disorders in peripheral myelin fibers, immobility and areflexia of the pupils, dry mucous membranes, orthostatic hypotension occur, heart rate slows down, intestinal motility is disturbed, and bladder hypotension occurs. Psychic functions, condition of muscles, including oculomotor muscles, coordination of movements, sensitivity remain intact. It is possible to change the sugar curve according to the diabetic type, in the CSF - an increase in the protein content. Acute autonomic dysfunction may gradually regress after some time, and in most cases recovery occurs.

13.3.10. Chronic autonomic dysfunction

Chronic autonomic dysfunction occurs with prolonged bed rest or in conditions of weightlessness. It is manifested mainly by dizziness, coordinating disorders, which, when returning to normal mode, gradually, over several days, decrease. Violation of autonomic functions can be triggered by an overdose of certain drugs. Thus, an overdose of antihypertensive drugs leads to orthostatic hypotension; when using drugs that affect thermoregulation, there is a change in vasomotor reactions and sweating.

Some diseases can cause secondary autonomic disorders. So, in diabetes mellitus and amyloidosis, manifestations of neuropathy are characteristic, in which severe orthostatic hypotension, changes in pupillary reactions, impotence, and bladder dysfunction are possible. When tetanus occurs arterial hypertension, tachycardia, hyperhidrosis.

13.3.11. Thermoregulation disorders

Thermoregulation can be represented as a cybernetic self-governing system, while the thermoregulatory center, which provides a set of physiological reactions of the body aimed at maintaining a relatively constant body temperature, is located in the hypothalamus and adjacent areas of the diencephalon. It receives information from thermoreceptors located in various organs and tissues. The thermoregulation center, in turn, through nerve connections, hormones and other biologically active substances regulates the processes of heat production and heat transfer in the body. With a disorder of thermoregulation (in an animal experiment - when the brain stem is cut), the body temperature becomes excessively dependent on the ambient temperature (poikilothermia).

The state of body temperature is influenced by conditioned different reasons changes in heat production and heat transfer. If the body temperature rises to 39 ° C, patients usually experience malaise, drowsiness, weakness, headache and muscle pain. At temperatures above 41.1 ° C, convulsions often occur in children. If the temperature rises to 42.2 °C and higher, irreversible changes in the brain tissue may occur, apparently due to protein denaturation. A temperature above 45.6 °C is incompatible with life. When the temperature drops to 32.8 ° C, consciousness is disturbed, at 28.5 ° C, atrial fibrillation begins, and even greater hypothermia causes ventricular fibrillation of the heart.

In violation of the function of the thermoregulatory center in the preoptic region of the hypothalamus (vascular disorders, more often hemorrhages, encephalitis, tumors), endogenous central hyperthermia. It is characterized by changes in daily fluctuations in body temperature, cessation of sweating, lack of reaction when taking antipyretic drugs, impaired thermoregulation, in particular, the severity of a decrease in body temperature in response to its cooling.

In addition to hyperthermia due to dysfunction of the thermoregulatory center, increased heat production may be associated with other reasons. She is possible in particular, with thyrotoxicosis (body temperature may be 0.5-1.1 ° C higher than normal), increased activation of the adrenal medulla, menstruation, menopause and other conditions accompanied by endocrine imbalance. Hyperthermia can also be caused by extreme physical exertion. For example, when running a marathon, body temperature sometimes rises to 39-41? Cause hyperthermia may also reduce heat transfer. Concerning hyperthermia is possible with congenital absence of sweat glands, ichthyosis, common skin burns, as well as taking medications that reduce sweating (M-cholinolytics, MAO inhibitors, phenothiazines, amphetamines, LSD, some hormones, especially progesterone, synthetic nucleotides).

More often than others, infectious agents are an exogenous cause of hyperthermia. (bacteria and their endotoxins, viruses, spirochetes, yeast fungi). There is an opinion that all exogenous pyrogens act on thermoregulatory structures through an intermediary substance - endogenous pyrogen (EP), identical to interleukin-1, which is produced by monocytes and macrophages.

In the hypothalamus, endogenous pyrogen stimulates the synthesis of prostaglandins E, which change the mechanisms of heat production and heat transfer by enhancing the synthesis of cyclic adenosine monophosphate. endogenous pyrogen, contained in the astrocytes of the brain, can be released during cerebral hemorrhage, traumatic brain injury, causing an increase in body temperature, at the same time, the neurons responsible for slow sleep can be activated. The latter circumstance explains lethargy and drowsiness during hyperthermia, which can be considered as one of the protective reactions. In infectious processes or acute inflammation hyperthermia plays an important role in the development of immune responses, which can be protective, but sometimes leading to an increase in pathological manifestations.

Permanent non-infectious hyperthermia (psychogenic fever, habitual hyperthermia) - permanent low-grade fever (37-38? C) for several weeks, less often - several months and even years. The temperature rises monotonously and does not have a circadian rhythm, accompanied by a decrease or cessation of sweating, lack of response to antipyretic drugs (amidopyrine, etc.), impaired adaptation to external cooling. Characteristic satisfactory tolerance of hyperthermia, job retention. Permanent non-infectious hyperthermia is more common in children and young women during periods of emotional stress and usually regarded as one of the signs of autonomic dystonia syndrome. However, especially in older people, it can also be the result of an organic lesion of the hypothalamus (tumor, vascular disorders, especially hemorrhage, encephalitis). A variant of psychogenic fever can, apparently, be recognized Hynes-Bennick syndrome (described by Hines-Bannick M.), arising as a result of autonomic imbalance, manifested by general weakness (asthenia), permanent hyperthermia, severe hyperhidrosis, goose bumps. May be caused by psychic trauma.

Temperature crises (paroxysmal non-infectious hyperthermia) - sudden rise in temperature up to 39-41 ºС, accompanied by a chill-like state, a feeling of internal tension, flushing of the face, tachycardia. The elevated temperature persists for several hours, after which its lytic decrease usually occurs, accompanied by general weakness, weakness, noted for several hours. Crises can occur against the background of normal body temperature or prolonged subfebrile condition (permanent-paroxysmal hyperthermia). With them, changes in the blood, in particular its leukocyte formula, are uncharacteristic. Temperature crises are one of the possible manifestations of autonomic dystonia and dysfunction of the thermoregulatory center, part of the hypothalamic structures.

Malignant hyperthermia - a group of hereditary conditions characterized by a sharp increase in body temperature to 39-42? C in response to the introduction of inhalation anesthetics, as well as muscle relaxants, especially dithylin, in this case, there is insufficient relaxation of the muscles, appearance of fasciculations in response to the introduction of dithylin. The tone of the masticatory muscles often increases, difficulty in intubation which may cause an increase in the dose of muscle relaxant and (or) anesthetic, leads to the development of tachycardia and in 75% of cases to generalized muscle rigidity (rigid form of reaction). Against this background, one can note high activity

creatine phosphokinase (CPK) and myoglobinuria, develop severe respiratory and metabolic acidosis and hyperkalemia, possibly ventricular fibrillation, decreased blood pressure, appears marble cyanosis, arises the threat of death.

The risk of developing malignant hyperthermia during inhalation anesthesia is especially high in patients suffering from Duchenne myopathy, central core myopathy, Thomsen's myotonia, chondrodystrophic myotonia (Schwartz-Jampel syndrome). It is assumed that malignant hyperthermia is associated with the accumulation of calcium in the sarcoplasm of muscle fibers. Tendency to malignant hyperthermia inherited in most cases in an autosomal dominant manner with different penetrance of the pathological gene. There is also malignant hyperthermia, inherited on recessive type(King's syndrome).

In laboratory studies in cases of malignant hyperthermia, signs of respiratory and metabolic acidosis, hyperkalemia and hypermagnesemia, an increase in the blood levels of lactate and pyruvate are revealed. Among the late complications of malignant hyperthermia, massive swelling of skeletal muscles, pulmonary edema, DIC, acute renal failure.

Neuroleptic malignant hyperthermia along with high body temperature, it is manifested by tachycardia, arrhythmia, instability of blood pressure, sweating, cyanosis, tachypnea, water-electrolyte balance with an increase in plasma potassium concentration, acidosis, myoglobinemia, myoglobinuria, increased activity of CPK, AST, ALT, signs of DIC appear. Muscle contractures appear and grow, a coma develops. Pneumonia, oliguria join. In pathogenesis, the role of impaired thermoregulation and disinhibition of the dopamine system of the tubero-infundibular region of the hypothalamus is important. Death occurs more often after 5-8 days. An autopsy reveals acute dystrophic changes in the brain and parenchymal organs. Syndrome develops due to long-term treatment neuroleptics, however, it can develop in patients with schizophrenia who have not taken antipsychotics, rarely in patients with parkinsonism who have been taking L-DOPA drugs for a long time.

chill syndrome - an almost constant feeling of chilliness throughout the body or in its individual parts: in the head, back, etc., usually combined with senestopathies and manifestations of the hypochondriacal syndrome, sometimes with phobias. Patients are afraid of cold weather, drafts, usually wear excessively warm clothes. Their body temperature is normal, in some cases permanent hyperthermia is detected. Considered as one of the manifestations of autonomic dystonia with a predominance of the activity of the parasympathetic division of the autonomic nervous system.

For the treatment of patients with non-infectious hyperthermia, it is advisable to use beta- or alpha-blockers (phentolamine 25 mg 2-3 times a day, pyrroxane 15 mg 3 times a day), restorative treatment. With sustained bradycardia, spastic dyskinesia, belladonna preparations (bellataminal, belloid, etc.) are prescribed. The patient should stop smoking and alcohol abuse.

13.3.12. Lacrimal disorders

The secretory function of the lacrimal glands is provided mainly by the influence on them of impulses coming from the parasympathetic lacrimal nucleus, located in the brain bridge near the nucleus of the facial nerve and receiving stimulating impulses from the structures of the limbic-reticular complex. From the parasympathetic lacrimal nucleus, impulses travel along the intermediate nerve and its branch - the large stony nerve - to the parasympathetic pterygopalatine ganglion. The axons of the cells located in this ganglion make up the lacrimal nerve, which innervates the secretory cells of the lacrimal gland. Sympathetic impulses travel to the lacrimal gland from the cervical sympathetic ganglia along the fibers of the carotid plexus and cause mainly vasoconstriction in the lacrimal glands. During the day, the human lacrimal gland produces approximately 1.2 ml of tear fluid. Tearing occurs mainly during periods of wakefulness and is inhibited during sleep.

Tearing disorders can be in the form of dry eyes due to insufficient production of tear fluid by the lacrimal glands. Excessive lacrimation (epiphora) is often associated with a violation of the outflow of tears into the nasal cavity through the nasolacrimal canal.

Dryness (xerophthalmia, alacrymia) of the eye may be a consequence of damage to the lacrimal glands themselves or a disorder of their parasympathetic innervation. Violation of the secretion of tear fluid - one of the characteristic features of Sjögren's dry mucous membrane syndrome (H.S. Sjogren), Riley-Day congenital dysautonomy, acute transient total dysautonomy, Mikulich syndrome. Unilateral xerophthalmia is more common in case of damage to the facial nerve, proximal to the place of departure from it of a branch - a large stony nerve. A typical picture of xerophthalmia, often complicated by inflammation of the tissues of the eyeball, is sometimes observed in patients operated on for neurinoma of the VIII cranial nerve, during which the fibers of the facial nerve deformed by the tumor were dissected.

In prosoplegia due to neuropathy of the facial nerve, in which this nerve is damaged below the origin of the large stony nerve from it, it usually occurs lacrimation, arising as a result of paresis of the circular muscle of the eye, lower eyelid and, in connection with this, a violation of the natural outflow of lacrimal fluid through the nasolacrimal canal. The same reason underlies senile lacrimation, associated with a decrease in the tone of the circular muscle of the eyes, as well as vasomotor rhinitis, conjunctivitis, leading to swelling of the wall of the nasolacrimal canal. Paroxysmal excessive lacrimation due to swelling of the walls of the nasolacrimal canal during a painful attack occurs with beam pain, attacks of autonomic prosopalgia. Lachrymation triggered by irritation of the zone of innervation of the I branch of the trigeminal nerve can be reflex with cold epiphora (lacrimation in the cold) deficiency of vitamin A, pronounced exophthalmos. Increased tearing while eating characteristic of crocodile tears syndrome, described in 1928 by F.A. Bogard. This syndrome can be congenital or occurs in the recovery stage of facial neuropathy. In parkinsonism, lacrimation can be one of the manifestations of the general activation of cholinergic mechanisms, as well as a consequence of hypomimia and rare blinking, which weakens the possibility of tear fluid outflow through the nasolacrimal canal.

Treatment of patients with lacrimation disorders depends on the causes that cause them. With xerophthalmia, it is necessary to monitor the condition of the eye and measures aimed at maintaining its moisture and preventing infection, instillation into the eyes oil solutions, albucida, etc. Recently began to use artificial lacrimal fluid.

13.3.13. salivation disorder

Dry mouth (hyposalivation, xerostomia) and excessive salivation (hypersalivation, sialorrhea) may be due to various reasons. Hypo- and hypersalivation may be permanent or paroxysmal in nature,

at night, the production of saliva is less, when eating and even at the sight of food, its smell, the amount of saliva secreted increases. Usually, from 0.5 to 2 liters of saliva is produced per day. Under the influence of parasympathetic impulses, the salivary glands produce abundant liquid saliva, while the activation of sympathetic innervation leads to the production of thicker saliva.

hypersalivationcommon in parkinsonism, bulbar and pseudobulbar syndrome, cerebral palsy; with these pathological conditions she is may be due to both hyperproduction of saliva and violations of the act of swallowing, the latter circumstance usually leads to a spontaneous flow of saliva from the mouth, even in cases of secretion of it in the usual amount. Hypersalivation may be the result of ulcerative stomatitis, helminthic invasion, toxicosis of pregnant women, in some cases it is recognized as psychogenic.

The cause of persistent hyposalivation (xerostomia) is Sjögren's syndrome(dry syndrome), in which xerophthalmia (dry eyes), dryness of the conjunctiva, nasal mucosa, dysfunction of other mucous membranes, swelling in the area of ​​​​the parotid salivary glands occur simultaneously. Hyposalivation is a sign of glossodynia, stomalgia, total dysautonomy, she can occur with diabetes mellitus, with diseases of the gastrointestinal tract, starvation, under the influence of certain drugs (nitrazepam, lithium preparations, anticholinergics, antidepressants, antihistamines, diuretics, etc.), during radiation therapy. Dry mouth usually occurs in excitement due to the predominance of sympathetic reactions, it is possible with a depressive state.

In case of violation of salivation, it is desirable to clarify its cause and then conduct a possible pathogenetic therapy. As a symptomatic remedy for hypersalivation, anticholinergics can be used, for xerostomia - bromhexine (1 tab 3-4 times a day), pilocarpine (capsules 5 mg sublingually 1 time a day), nicotinic acid, vitamin A preparations. As a replacement treatment artificial saliva is used.

13.3.14. Sweating disorders

Sweating is one of the factors affecting thermoregulation, and is in a certain dependence on the state of the thermoregulatory center, which is part of the hypothalamus and has a global

influence on the sweat glands, which, according to the morphological features, location and chemical composition of the sweat they secrete, are differentiated into merocrine and apocrine glands, while the role of the latter in the occurrence of hyperhidrosis is insignificant.

Thus, the thermoregulation system consists mainly of certain structures of the hypothalamus (preoptic zone of the hypothalamic region) (Guyton A., 1981), their connections with the skin integumentary and merocrine sweat glands located in the skin. The hypothalamic part of the brain, through the autonomic nervous system, regulates heat transfer by controlling the state of skin vascular tone and the secretion of sweat glands,

while most of the sweat glands have sympathetic innervation, but the mediator of the postganglionic sympathetic fibers suitable for them is acetylcholine. There are no adrenergic receptors in the postsynaptic membrane of the merocrine sweat glands, but some cholinergic receptors can also respond to adrenaline and noradrenaline circulating in the blood. It is generally accepted that only the sweat glands of the palms and soles have dual cholinergic and adrenergic innervation. This explains their increased sweating during emotional stress.

Increased sweating may be a normal response to external stimuli (heat exposure, exercise, excitement). However, excessive, persistent, localized or generalized hyperhidrosis may be the result of some organic neurological, endocrine, oncological, general somatic, and infectious diseases. In cases of pathological hyperhidrosis, the pathophysiological mechanisms are different and are determined by the characteristics of the underlying disease.

Local pathological hyperhidrosis observed relatively rarely. In most cases, this is the so-called idiopathic hyperhidrosis, in which excessive sweating is noted mainly on the palms, feet, in the axillary region. It appears from the age of 15-30, more often in women. Over time, excessive sweating may gradually stop or become chronic. This form of local hyperhidrosis is usually combined with other signs of vegetative lability, and is often noted in the patient's relatives.

Hyperhidrosis associated with eating or hot drinks, especially coffee, spicy dishes, also belongs to local ones. Sweat comes out primarily on the forehead and on the upper lip. The mechanism of this form of hyperhidrosis has not been clarified. More certain is the cause of local hyperhidrosis in one of the forms vegetative prosopalgia - Bayarger-Frey syndrome, described in French mi doctors - in 1847 J. Baillarger (1809-1890) and in 1923 L. Frey (auriculotemporal syndrome), resulting from damage to the ear-temporal nerve due to inflammation of the parotid salivary gland. Mandatory pro- the phenomenon of an attack in this disease is hyperemia of the skin and increased sweating in the parotid-temporal region. The occurrence of seizures is usually provoked by the intake of hot food, general overheating, smoking, physical work, emotional stress. Bayarger-Frey syndrome can also occur in newborns in whom the facial nerve has been damaged during delivery using forceps.

drum string syndrome characterized by increased sweating in the chin area, usually in response to a taste sensation. It occurs after operations on the submandibular gland.

Generalized hyperhidrosis occurs much more often than local. Physiological its mechanisms are different. Here are some of the conditions that cause hyperhidrosis.

1. Thermoregulatory sweating, which occurs throughout the body in response to an increase in ambient temperature.

2. Generalized excessive sweating can be a consequence of psychogenic stress, a manifestation of anger and especially fear, hyperhidrosis is one of the objective manifestations of intense pain felt by the patient. However, with emotional reactions, sweating can also be in limited areas: face, palms, feet, armpits.

3. Infectious diseases and inflammatory processes, in which pyrogenic substances appear in the blood, which leads to the formation of a triad: hyperthermia, chills, hyperhidrosis. The nuances of development and the course of the components of this triad often depend on the characteristics of the infection and the state of the immune system.

4. Changes in the level of metabolism in some endocrine disorders: acromegaly, thyrotoxicosis, diabetes mellitus, hypoglycemia, climacteric syndrome, pheochromocytoma, hyperthermia of various origins.

5. Oncological diseases (primarily cancer, lymphoma, Hodgkin's disease), in which the products of metabolism and tumor decay enter the blood, giving a pyrogenic effect.

Pathological changes in sweating are possible with lesions of the brain, accompanied by a violation of the functions of its hypothalamic department. Acute cerebrovascular accidents, encephalitis, volumetric pathological processes in the cranial cavity can provoke sweating disorders. With parkinsonism, hyperhidrosis on the face is often noted. Hyperhidrosis of central origin is characteristic of familial dysautonomy (Riley-Day syndrome).

The state of sweating is influenced by many drugs (aspirin, insulin, some analgesics, cholinomimetics and anticholinesterase agents - prozerin, kalemin, etc.). Hyperhidrosis can be provoked by alcohol, drugs, it can be one of the manifestations of the withdrawal syndrome, withdrawal reactions. Pathological sweating is one of the manifestations of organophosphate poisoning (OPS).

It occupies a special place essential form of hyperhidrosis, in which the morphology of the sweat glands and the composition of sweat are not changed. The etiology of this condition is unknown, pharmacological blockade of the activity of the sweat glands does not bring sufficient success.

In the treatment of patients with hyperhidrosis, M-anticholinergics (cyclodol, akineton, etc.), small doses of clonidine, sonapax, beta-blockers can be recommended. Topically applied astringents are more effective: solutions of potassium permanganate, aluminum salts, formalin, tannic acid.

Anhidrosis(no sweating) may be due to sympathectomy. Spinal cord injury is usually accompanied by anhidrosis on the trunk and extremities below the lesion. With complete Horner's syndrome along with the main signs (miosis, pseudoptosis, endophthalmos) on the face on the side of the lesion, skin hyperemia, dilation of the conjunctival vessels and anhidrosis can usually be noted. Anhidrosis can be seen in the area innervated by damaged peripheral nerves. Anhidrosis on the body

and lower limbs may be a consequence of diabetes in such cases, patients do not tolerate heat well. They may have increased sweating on the face, head, neck.

13.3.15. Alopecia

Alopecia neurotic (Mikhelson's alopecia) - baldness resulting from neurotrophic disorders in diseases of the brain, primarily the structures of the diencephalic part of the brain. Treatment of this form of neurotrophic process has not been developed. Alopecia can be the result of X-ray or radioactive exposure.

13.3.16. Nausea and vomiting

Nausea(nausea)- a kind of painful sensation in the pharynx, in the epigastric region of impending urge to vomit, signs of beginning antiperistalsis. It occurs as a result of excitation of the parasympathetic division of the autonomic nervous system, for example, with excessive irritation of the vestibular apparatus, the vagus nerve. Accompanied by pallor, hyperhidrosis, profuse salivation, often - bradycardia, arterial hypotension.

Vomit(vomitus, emesis)- a complex reflex act, manifested by involuntary ejection, eruption of the contents of the digestive tract (mainly the stomach) through the mouth, less often through the nose. It may be due to direct irritation of the vomiting center - the chemoreceptor zone located in the tegmentum of the medulla oblongata (cerebral vomiting). Such an irritating factor can be a focal pathological process (tumor, cysticercosis, hemorrhage, etc.), as well as hypoxia, the toxic effect of anesthetics, opiates, etc.). brain vomiting occurs more frequently as a result of intracranial pressure, often it manifests itself in the morning on an empty stomach, usually without precursors and has a gushing character. The cause of cerebral vomiting can be encephalitis, meningitis, brain injury, brain tumor, acute disorder cerebral circulation, cerebral edema, hydrocephalus (all its forms, except vicarious, or replacement).

psychogenic vomiting - possible manifestation neurotic reaction, neurosis, mental disorders.

Often the cause of vomiting are various factors that secondarily irritate the vagus nerve receptors at different levels: in the diaphragm, organs of the digestive tract. In the latter case, the afferent part of the reflex arc is mainly the main, sensitive portion of the vagus nerve, and the efferent part is the motor portions of the trigeminal, glossopharyngeal and vagus nerves. Vomiting may also a consequence of overexcitation of the vestibular apparatus (seasickness, Meniere's disease, etc.).

The act of vomiting consists of successive contractions of various muscle groups (diaphragm, abdominals, pylorus, etc.), while the epiglottis descends, the larynx and soft palate rise, which leads to isolation (not always sufficient) of the respiratory tract from getting into them emetic

wt. Vomiting may be defensive reactions digestive system to get into it or the formation of toxic substances in it. In a severe general condition of the patient, vomiting can cause aspiration of the respiratory tract, repeated vomiting is one of the causes of dehydration.

13.3.17. hiccup

hiccup(singultus)- involuntary myoclonic contraction of the respiratory muscles, simulating a fixed breath, while suddenly the airways and the air flow passing through them are blocked by the epiglottis and a characteristic sound occurs. In healthy people, hiccups can be the result of diaphragm irritation caused by overeating, drinking chilled drinks. In such cases, hiccups are single, short-term. Persistent hiccups may be the result of irritation of the lower parts of the brain stem in case of cerebrovascular accident, subtentorial tumor or traumatic injury to the brain stem, increasing intracranial hypertension, and in such cases it is a sign signaling a threat to the patient's life. Dangerous can also be irritation of the spinal nerve C IV, as well as the phrenic nerve with a tumor of the thyroid gland, esophagus, mediastinum, lungs, arteriovenous malformation, lymphoma of the neck, etc. The cause of hiccups can also be gastrointestinal diseases, pancreatitis, subdiaphragmatic abscess, as well as intoxication alcohol, barbiturates, drugs. Repeated hiccups are also possible as one of the manifestations of a neurotic reaction.

13.3.18. Disorders of the innervation of the cardiovascular system

Disorders of the innervation of the heart muscle affect the state of general hemodynamics. The absence of sympathetic influences on the heart muscle limits the increase in the stroke volume of the heart, and the insufficiency of the influences of the vagus nerve leads to the appearance of tachycardia at rest, while possible various options arrhythmias, lipothymia, syncope. Violation of the innervation of the heart in patients with diabetes mellitus leads to similar phenomena. General vegetative disorders may be accompanied by attacks of orthostatic blood pressure drop that occur during sudden movements, when the patient tries to quickly take a vertical position. Vegetative-vascular dystonia can also be manifested by pulse lability, changes in the rhythm of cardiac activity, a tendency to angiospastic reactions, in particular to vascular headaches, a variant of which are various forms migraine.

In patients with orthostatic hypotension, a sharp decrease in blood pressure is possible under the influence of many drugs: antihypertensive drugs, tricyclic antidepressants, phenothiazines, vasodilators, diuretics, insulin. The denervated human heart functions in accordance with the Frank-Starling rule: the force of contraction of myocardial fibers is proportional to the initial amount of their stretching.

13.3.19. Violation of the sympathetic innervation of the smooth muscles of the eye (Bernard-Horner syndrome)

Bernard-Horner Syndrome, or Horner's syndrome. Sympathetic innervation of the smooth muscles of the eye and its appendages is provided by nerve impulses coming from the nuclear structures of the posterior part of the hypothalamic part of the brain, which pass through the descending pathways through the brainstem and cervical part of the spinal cord and end in the Jacobson cells that form the C VIII -D I segments in the lateral horns spinal cord ciliospinal center of Buje-Weller. From it, along the axons of Jacobson cells passing through the corresponding anterior roots, spinal nerves and white connecting branches, they enter the cervical region of the paravertebral sympathetic chain, reaching the upper cervical sympathetic ganglion. Further, the impulses continue along the postganglionic fibers, which take part in the formation of the sympathetic plexus of the common and internal carotid arteries, and reach the cavernous sinus. From here they, together with the ophthalmic artery, enter the orbit and innervate the following smooth muscles: dilator muscle, orbital muscle, and cartilage muscle upper eyelid (m. dilatator pupillae, m. orbitalis and m. tarsalis superior).

Violation of the innervation of these muscles, which occurs when any part of the path of sympathetic impulses coming from the posterior hypothalamus to them, leads to their paresis or paralysis. In this regard, on the side of the pathological process, Horner Syndrome, or Claude Bernard-ra-Horner, emerging constriction of the pupil (paralytic miosis), slight enophthalmos and the so-called pseudoptosis (drooping of the upper eyelid), causing some narrowing of the palpebral fissure (Fig. 13.3). Due to the preservation of the parasympathetic innervation of the sphincter of the pupil on the side of Horner's syndrome, the reaction of the pupil to light remains intact.

In connection with a violation on the homolateral half of the face of vasoconstrictor reactions Horner's syndrome is usually accompanied by hyperemia of the conjunctiva, skin, heterochromia of the iris and impaired sweating are also possible. A change in sweating on the face can help clarify the topic of damage to sympathetic structures in Horner's syndrome. With postganglionic localization of the process, violation of sweating on the face is limited to one side of the nose and the paramedial area of ​​the forehead. If sweating is disturbed on the entire half of the face, the lesion of the sympathetic structures is preganglionic.

Since ptosis of the upper eyelid and narrowing of the pupil can have a different origin, in order to make sure that in this case there are manifestations of Horner's syndrome, you can check the reaction of the pupils to the instillation of an M-anticholinergic solution into both eyes. After that, with Horner's syndrome, pronounced anisocoria will appear, since on the side of the manifestations of this syndrome, pupil dilation will be absent or will appear slightly.

Thus, Horner's syndrome indicates a violation of the sympathetic innervation of the smooth muscles of the eye and the corresponding half of the face. It may be the result of damage to the nuclei of the posterior part of the hypothalamus, the central sympathetic pathway at the level of the brain stem or cervical spinal cord, the ciliospinal center, the preganglionic fibers extending from it,

Rice. 13.3.Sympathetic innervation of the eye.

a - diagram of pathways: 1 - vegetative cells of the hypothalamus; 2 - ophthalmic artery; 3 - internal carotid artery; 4, 5 - middle and upper nodes of the paravertebral sympathetic chain; 6 - star knot; 7 - body of a sympathetic neuron in the ciliospinal center of the spinal cord; b - the appearance of the patient with a violation of the sympathetic innervation of the left eye (Bernard-Horner syndrome).

the upper cervical ganglion and the postganglionic sympathetic fibers coming from it, forming the sympathetic plexus of the external carotid artery and its branches. The cause of Horner's syndrome can be lesions of the hypothalamus, brain stem, cervical spinal cord, sympathetic structures in the neck, plexus of the external carotid artery and its branches. Such lesions can be caused by trauma to the indicated structures of the central nervous system and peripheral nervous system, a voluminous pathological process, cerebrovascular diseases, and sometimes demyelination in multiple sclerosis. An oncological process, accompanied by the development of Horner's syndrome, may be cancer of the upper lobe of the lung, germinating into the pleura (Pancoast cancer).

13.3.20. Innervation of the bladder and its disorders

Of great practical importance is the identification of violations of the functions of the bladder, which occurs in connection with the disorder of its innervation, which is provided mainly by the autonomic nervous system (Fig. 13.4).

Afferent somatosensory fibers originate from the proprioreceptors of the bladder, which react to its stretching. The nerve impulses arising in these receptors penetrate through the spinal nerves S II -S IV

Rice. 13.4.Bladder innervation [according to Müller].

1 - paracentral lobule; 2 - hypothalamus; 3 - upper lumbar spinal cord; 4 - lower sacral spinal cord; 5 - bladder; 6 - genital nerve; 7 - hypogastric nerve; 8 - pelvic nerve; 9 - plexus of the bladder; 10 - bladder detrusor; 11 - internal sphincter of the bladder; 12 - external sphincter of the bladder.

into the posterior cords of the spinal cord, then enter the reticular formation of the brain stem and further - in the paracentral lobules of the cerebral hemispheres, in this case, along the route, part of these impulses passes to the opposite side.

Thanks to the information going through the indicated peripheral, spinal and cerebral structures to the paracentral lobules, the expansion of the bladder during its filling is realized, and the presence of an incomplete re-

the cross of these afferent pathways leads to the fact that with cortical localization of the pathological focus, a violation of the control of pelvic functions usually occurs only when both paracentral lobules are affected (for example, with falx meningioma).

Efferent innervation of the bladder carried out mainly due to the paracentral lobules, the reticular formation of the brain stem and spinal autonomic centers: sympathetic (neurons of the lateral horns of the Th XI -L II segments) and parasympathetic, located at the level of the spinal cord segments S II -S IV. Conscious regulation of urination is carried out mainly due to nerve impulses coming from the motor zone of the cerebral cortex and the reticular formation of the trunk to the motor neurons of the anterior horns of segments S III -S IV. It is clear that to ensure the nervous regulation of the bladder, it is necessary to preserve the pathways connecting these structures of the brain and spinal cord to each other, as well as the formations of the peripheral nervous system that provide innervation of the bladder.

Preganglionic fibers coming from the lumbar sympathetic center of the pelvic organs (L 1 -L 2) pass as part of the presacral and hypogastric nerves, in transit through the caudal sections of the sympathetic paravertebral trunks and along the lumbar splanchnic nerves (nn. splanchnici lumbales), they reach the nodes of the inferior mesenteric plexus (plexus mesentericus inferior). The postganglionic fibers coming from these nodes take part in the formation of the nerve plexuses of the bladder and provide innervation, primarily to its internal sphincter. Due to sympathetic stimulation of the bladder, the internal sphincter formed by smooth muscles is contracted; at the same time, as the bladder fills, the muscle of its wall stretches - the muscle that pushes urine out (m. detrusor vesicae). All this ensures the retention of urine, which is facilitated by the simultaneous contraction of the external striated sphincter of the bladder, which has somatic innervation. Her exercise sexual nerves (nn. pudendi), consisting of axons of motor neurons located in the anterior horns of the S III S IV segments of the spinal cord. Efferent impulses to the pelvic floor muscles and counterproprioceptive afferent signals from these muscles also pass through the pudendal nerves.

Parasympathetic innervation of the pelvic organs carry out preganglionic fibers coming from the parasympathetic center of the bladder, located in the sacral spinal cord (S I -S III). They participate in the formation of the pelvic plexus and reach the intramural (located in the wall of the bladder) ganglia. Parasympathetic stimulation causes contraction of the smooth muscle that forms the body of the bladder (m. detrusor vesicae), and the concomitant relaxation of its smooth sphincters, as well as increased intestinal motility, which creates the conditions for emptying the bladder. Involuntary spontaneous or provoked contraction of the bladder detrusor (detrusor overactivity) leads to urinary incontinence. Detrusor overactivity can be neurogenic (eg, in multiple sclerosis) or idiopathic (in the absence of an identified cause).

Urinary retention (retentio urinae) more often occurs due to damage to the spinal cord above the location of the spinal sympathetic autonomic centers (Th XI -L II), responsible for the innervation of the bladder.

Urinary retention leads to dyssynergy of the state of the detrusor and sphincters of the bladder (contraction of the internal sphincter and relaxation of the detrusor). So

it happens, for example, in traumatic lesions of the spinal cord, intravertebral tumor, multiple sclerosis. The bladder in such cases overflows and its bottom can rise to the level of the navel and above. Urinary retention is also possible due to damage to the parasympathetic reflex arc, which closes in the sacral segments of the spinal cord and provides innervation of the bladder detrusor. The cause of paresis or paralysis of the detrusor can be either a lesion of the indicated level of the spinal cord, or a dysfunction of the structures of the peripheral nervous system that make up the reflex arc. In cases of persistent urinary retention, patients usually need to empty the bladder through a catheter. Simultaneously with urinary retention, there is usually neuropathic fecal retention. (retencia alvi).

Partial damage to the spinal cord above the level of the location of the autonomic spinal centers responsible for the innervation of the bladder can lead to a violation of voluntary control over urination and the emergence of the so-called imperative urge to urinate, in which the patient, feeling the urge, is not able to hold urine. A large role is likely to be played by the violation of the innervation of the external sphincter of the bladder, which normally can be controlled to a certain extent by willpower. Such manifestations of dysfunction of the bladder are possible, in particular, with bilateral lesions of the medial structures of the lateral cords in patients with an intramedullary tumor or multiple sclerosis.

A pathological process that affects the spinal cord at the level of the location of the sympathetic vegetative centers of the bladder in it (cells of the lateral horns of Th I -L II segments of the spinal cord) leads to paralysis of the internal sphincter of the bladder, while the tone of its protrusor is increased, in connection with this, there is a constant excretion of urine in drops - true urinary incontinence (incontinentia urinae vera) as it is produced by the kidneys, the bladder is practically empty. True urinary incontinence may be due to a spinal stroke, spinal cord injury, or a spinal tumor at the level of these lumbar segments. True urinary incontinence can also be associated with damage to the structures of the peripheral nervous system involved in the innervation of the bladder, in particular in diabetes mellitus or primary amyloidosis.

With urinary retention due to damage to the structures of the central or peripheral nervous system, it accumulates in the overdistended bladder and can create so much high pressure that under its influence there is a stretching of the internal and external sphincters of the bladder that are in a state of spastic contraction. In this regard, urine is constantly excreted in drops or periodically in small portions through the urethra while maintaining the overflow of the bladder - paradoxical urinary incontinence (incontinentia urinae paradoxa), which can be established by visual examination, as well as by palpation and percussion of the lower abdomen, protrusion of the bottom of the bladder above the pubis (sometimes up to the navel).

With damage to the parasympathetic spinal center (segments of the spinal cord S I -S III) and the corresponding roots of the cauda equina, weakness may develop and a simultaneous violation of the sensitivity of the muscle that ejects urine (m. detrusor vesicae), this results in urinary retention.

However, in such cases, over time, it is possible to restore the reflex emptying of the bladder, it begins to function in an "autonomous" mode. (autonomous bladder).

Clarification of the nature of bladder dysfunction can help determine the topical and nosological diagnoses of the underlying disease. In order to clarify the features of disorders of the functions of the bladder, along with a thorough neurological examination, according to indications, radiography of the upper urinary tract, bladder and urethra using radiopaque solutions. The results of urological examinations, in particular cystoscopy and cystometry (determination of pressure in the bladder during filling with liquid or gas), can help clarify the diagnosis. In some cases, electromyography of the periurethral striated muscles may be informative.

This regulation is carried out without conscious control, i.e. offline. There are two main divisions of the BHC: sympathetic and parasympathetic.

Disruption of the autonomic nervous system leads to autonomic failure and can affect any organ system.

The structure of the autonomic nervous system

The autonomic nervous system receives impulses from various parts of the central nervous system involved in the processing and integration of information about the state of the internal environment of the body and exposure to stimuli from the environment.

The sympathetic and parasympathetic divisions each have two types of nerve cells: preganglionic (located in the CNS) and cells connected to them, located in the ganglia outside the CNS. Efferent fibers are directed from the peripheral ganglia to the effector organs.
Sympathetic division of the autonomic nervous system. The sympathetic ganglia are located adjacent to the spinal cord and are subdivided into vertebral and prevertebral ganglia, including the superior cervical, celiac, superior mesenteric, inferior mesenteric, and aortorenal ganglia. Long fibers follow from these ganglia to the effector organs, in particular to the smooth muscles of the blood vessels, visceral organs, lungs and scalp (the muscles that raise the hair), to the pupils, and to the heart and glands.

Parasympathetic division of the autonomic nervous system. Preganglionic fibers leave the brainstem as part of the 3rd, 7.9th and 10th (vagus) cranial nerves, and depart from the spinal cord at the level of the S2 and S3 segments; The vagus nerve contains about 75% of all parasympathetic fibers. The parasympathetic ganglia (eg, the ciliary, pterygopalatine, ear, pelvic, and vagus ganglia) are located within the effector organs, and therefore the postganglionic fibers are 1 to 2 mm long. Thus, the parasympathetic nervous system provides a specific local response of effector organs.

Physiology of the autonomic nervous system

VIS is responsible for the regulation of blood pressure, body temperature, body weight, digestion, metabolic rate, sexual function and other processes.

The sympathetic nervous system has a catabolic effect; it activates the fight-or-flight response. The parasympathetic nervous system has an anabolic effect; she saves and restores.

There are two main neurotransmitters in the autonomic nervous system.

• Acetylcholine: Cholinergic fibers (releasing acetylcholine) include all preganglionic, postganglionic parasympathetic and some postganglionic sympathetic fibers.
• Norepinephrine: Most postganglionic sympathetic fibers are noradrenergic (releasing norepinephrine). To some extent, the sweat glands on the palms and soles also respond to adrenergic stimulation.

There are several subtypes of adrenoreceptors and cholinergic receptors with different localization.

The reasons

The most common causes of autonomic failure include:

• polyneuropathy;
• aging;
• Parkinson's disease.

Other reasons include:

• autoimmune polyneuropathy with damage to autonomic fibers;
• multisystem atrophy;
• spinal cord injury;
• diseases with damage to the neuromuscular apparatus (for example, botulism, Lambert-Eaton syndrome).

Survey

Anamnesis. The following symptoms suggest autonomic failure:

• orthostatic hypotension;
• heat intolerance;
• impaired control of urination and defecation;
• erectile dysfunction ( early symptom). Other possible symptoms include dry eyes and dry mouth, but these are less specific.

Physical examination. Important points of the physical examination include:

• Blood pressure assessment.
• Eye examination: miosis and slight ptosis (Horner's syndrome) testify in favor of a violation of sympathetic innervation. An enlarged pupil with a loss of its reaction to light is a sign of a violation of parasympathetic innervation.
• Evaluation of reflexes caused from the genitourinary organs and rectum: their changes may also indicate a violation of the autonomic function.

Laboratory research. If the patient has symptoms that suggest autonomic failure, in order to clarify the severity and degree of involvement of various organs and systems in the pathological process, as a rule, sudomotor and cardio-vagal tests, as well as tests for adrenergic insufficiency, are performed.

Sudomotor tests include:

• quantitative assessment of the sudomotor axon reflex. This test evaluates the integrity of postganglionic neurons using acetylcholine drug electrophoresis; electrodes placed on the wrists and legs stimulate the sweat glands in this way, after which the amount of sweat released is measured. With this test, you can detect a decrease in sweating or its absence;
• thermoregulatory assessment of sweating. This test evaluates the function of both preganglionic and postganglionic fibers. A special dye is applied to the skin of the subject, after which the patient is placed in a closed heated room in order to cause maximum sweating. The release of sweat leads to a change in the color of the dye, which makes it possible to identify zones of anhidrosis and hypohidrosis and calculate their area as a percentage of the total body surface area.

If the autonomic system is functioning properly, the heart rate changes in response to these maneuvers; the normal response to these tests varies with the age of the patient.

Tests for adrenergic insufficiency assess the change in blood pressure in response to:

• transition of the body from a horizontal to a vertical position;
• Valsalva test.

Thus, the nature of the response to the two above-mentioned tests gives an idea of ​​adrenergic regulation.

If the patient has autonomic failure, especially in the presence of postganglionic lesions (for example, with polyneuropathy with damage to autonomic fibers and with primary autonomic failure), when moving to a standing position, the concentration of norepinephrine does not change or decreases.

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Since the ANS works in a secret mode, many are interested in what the autonomic nervous system is. In fact, it carries out very important activities within the body. Thanks to her, we breathe properly, blood circulation occurs, our hair grows, the pupils adjust to the lighting of the world around us, and hundreds of other processes take place that we do not follow. That is why the average person who has not experienced failures in this part of the nervous system does not even suspect its existence.

All work of the vegetative system is carried out by neurons within the human nervous system. Thanks to them and their signals, individual organs receive the appropriate "orders" or "messages". All signals come from the brain and spinal cord. Neurons, among other things, are responsible for the functioning of the salivary glands, the functioning of the gastrointestinal tract and the functioning of the heart. If you are observed, you probably noticed how in a stressful situation your stomach starts to twist, constipation appears, or vice versa, you urgently need to go to the toilet, your heart rate also increases, and saliva quickly accumulates in your mouth. These are just some of the symptoms. incorrect operation vegetative system.

You need to know what the autonomic nervous system consists of if you suffer from its disorder. The autonomic nervous system is divided into sympathetic and parasympathetic. We have already touched on this topic a little earlier, however, now we will consider it in more detail.

As mentioned above, the autonomic nervous system is involved in many processes. For clarity, we advise you to study the following images, which show the organs that are affected by the ANS. The general plan of the structure of the autonomic nervous system is as follows.

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The system responds to stimuli coming from outside or inside the body. Every second it performs a certain work, which we do not even know about. it prime example that the body lives independently of our conscious life. So, the autonomic part of the nervous system is primarily responsible for the work of breathing, circulation, hormone levels, excretion and heartbeat. There are three types of control that this department of the nervous system exercises.

1. Point impact on individual organs, for example, on the work of the gastrointestinal tract - functional control.
2. Trophic control is responsible for the metabolism at the cellular level in individual organs of the body.
3. Vasomotor control controls the level of blood flow to a particular organ.

command centers

The two main centers that determine the value of the autonomic nervous system, from where all commands come from, are the spinal cord and the brain stem. They give the necessary signals to certain departments in order to build the work of the organs.

• The sacral and sacral centers are responsible for the functioning of the pelvic organs.
• Thoracolumbar centers are located in the spinal cord from 2-3 lumbar segments to 1 thoracic.
• Bulbar department (medulla oblongata), is responsible for the work of the facial nerves, glossopharyngeal and vagus.
• The mesencephalic region is responsible for the work of the pupillary reflex.

To make the physiology of the autonomic nervous system and its work visual, study the following picture.

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As you can see, the sympathetic and parasympathetic divisions are responsible for completely opposite commands. When disturbances in the work of the ANS occur, the patient experiences certain problems with one or another organ, since the regulation does not work properly and a large number of signals are sent to a specific part of the body.

Vegetative system disorders

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Today it cannot be said that the autonomic nervous system has been fully studied, since active research and development is still underway. However, in 1991, Academician Wayne identified the main classification of disorders of the vegetative department. Modern scientists use the classification developed by American specialists.

• Disorders of the central part of the autonomic nervous system: isolated autonomic failure, Shy-Drager syndrome, Parkinson's disease.
• catecholamine disorders.
• Orthostatic tolerance disorders: postural tachycardia syndrome, orthostatic hypotension, neurogenic syncope.
• Peripheral disorders: familial dysautonomia, GBS, diabetic disorders.

Using medical terms, few people will understand the essence of diseases, so it is easier to write about the main symptoms. Those suffering from vegetative disorder react strongly to changes in the environment: humidity, fluctuations in atmospheric pressure, air temperature. There is a sharp decrease in physical activity, it is difficult for a person psychologically and emotionally.

• With damage to the hypothalamus, failures in the innervation of blood vessels and arteries are observed.
• Diseases that affect the hypothalamus (trauma, hereditary or congenital tumors, subarachnoid hemorrhage) affect thermoregulation, sexual function, and obesity is possible.
• Children sometimes have Prader-Willi syndrome: muscular hypotension, obesity, hypogonadism, slight mental retardation. Kleine-Levin syndrome: hypersexuality, drowsiness, bulimia.
• General symptoms are expressed in the manifestation of aggressiveness, malice, paroxysmal drowsiness, increased appetite and asocial instability.
• dizziness, palpitations, spasms of cerebral vessels are observed.

Dysfunction

When the malfunction of several organs is disturbed, which cannot be explained in any way by a medical doctor, most likely the patient has a dysfunction of the autonomic nervous system. All symptoms are the result not of physical diseases, but of nervous disorders. This dysfunction is also known as vegetovascular dystonia or neurocirculatory. All problems are related exclusively to the work of internal organs. Violation of the autonomic nervous system can manifest itself as follows.

• Hormonal imbalance;
• Overwork;
• Psycho-emotional stress;
• Depression;
• exposure to stress;
• Endocrine pathologies;
• Chronic diseases of the cardiovascular and digestive systems.

Symptoms

Interestingly, dysfunction can manifest itself in completely different ways, which makes it difficult to diagnose. Initially, the patient has to undergo many examinations in order to exclude physiological pathologies. The features of the autonomic nervous system are diverse, and therefore all the symptoms should be divided into subgroups.

1. Respiratory system:

• Hyperventilation syndrome;
• Suffocation;
• Dyspnea;
• Difficulty exhaling and inhaling.

2. Heart:

• Jumps in blood pressure;
• Increased heartbeat;
• Fluctuating heart rate;
• Chest pain, discomfort.

3. Digestive organs:

• abdominal stress;
• Dyspeptic disorders;
• Belching with air;
• Increased peristalsis.

4. Mind:

• sleep disorders;
• Resentment, irritability;
• Poor concentration;
• Unreasonable worries, anxieties and fears.

5. Skin and mucous membranes:

• increased sweating;
• dry mouth;
• tingling and numbness;
• Hand tremor;
• Spotted hyperemia, redness, cyanosis of the skin.

6. Motor-support device:

• Pain in the muscles;
• Feeling of a lump in the throat;
• Motor restlessness;
• Tension headaches;
• Muscle spasms and convulsions.

7. Urogenital systems:

• Frequent urination;
• Premenstrual syndrome.

Most often, patients experience vegetative dystonia according to. This means that symptoms from several groups appear simultaneously or alternately. Mixed dystonia is also accompanied by the following symptoms:

• feeling of chills;
• Asthenia;
• Fainting, dizziness;
• Subfebrile body temperature;
• fatigue.

It is worth noting that the autonomic nervous system innervates all organs and tissues if the sympathetic department is disturbed. The parasympathetic division does not innervate skeletal muscles, receptors, the central nervous system, the walls of some vessels, the uterus, the adrenal medulla.

Centers of the autonomic nervous system

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All centers of the autonomic nervous system are located in the medulla oblongata, spinal and midbrain, cerebral cortex, cerebellum, hypothalamus and reticular formation. Like everything in nature, the body is subject to a hierarchy when lower section subordinate to the higher. The lowest center is responsible for the regulation of physical functions, and those located above take on higher vegetative functions. Since the autonomic nervous system consists of the parasympathetic and sympathetic divisions, they also have different centers, respectively.

• The sympathetic department, or rather, the first three ANS neurons are located from 3-4 segments of the lumbar to the first thoracic (the middle and medulla oblongata, the posterior nuclei of the hypothalamus and the anterior horns of the spinal cord are responsible for the work).
• Parasympathetic is located in the 2-4 segment of the sacral spinal cord (mid and medulla oblongata, anterior hypothalamus).

Picks

Analyzing the topic of vegetovascular dystonia, one cannot ignore the mediators of the autonomic nervous system. These chemical compounds play a very important role in the functioning of the entire system, as they transmit nerve impulses from cell to cell, so that the body works smoothly and harmoniously.

The first key mediator is called acetylcholine, which is responsible for the work of the parasympathetic department. Thanks to this mediator, blood pressure decreases, the work of the heart muscle is reduced, and peripheral blood vessels expand. Under the action of acetylcholine, the smooth muscles of the walls of the bronchial tree are reduced, and the motility of the gastrointestinal tract is enhanced.

The second important neurotransmitter is called norepinephrine. Thanks to his work, the motor apparatus is activated in a stressful or shock situation, mental activity increases dramatically. Since it is responsible for the work of the sympathetic department, norepinephrine regulates the level of blood pressure, narrows the lumen of blood vessels, increases blood volume, and enhances the work of the heart muscles. Unlike adrenaline, this neurotransmitter does not affect the functioning of smooth muscles, but is much more capable of narrowing blood vessels.

There is a link through which the sympathetic and parasympathetic departments coordinate with each other. The following mediators are responsible for this connection: histamine, serotonin, adrenaline and others.

ganglia

The ganglia of the autonomic nervous system also play an important role, as many nerve signals pass through them. Among other things, they are also divided into ganglia of the sympathetic and parasympathetic divisions (located on both sides of the spine). In the sympathetic department, depending on the localization, they are divided into prevertebral and paravertebral. The ganglia of the parasympathetic division, in contrast to the sympathetic, are located inside the organs or next to them.

reflexes

If we talk about the reflexes of the autonomic nervous system, then you should know that they are divided into trophic and functional. So, the trophic influence consists in correcting the work of some organs, and the functional one consists either in the complete inhibition of work or vice versa, in full start (irritation). Vegetative reflexes are usually divided into the following groups:

• Viscero-somatic. Excitation of the receptors of the internal organs leads to a change in the tone of the skeletal muscles.
• Viscero-visceral. In this case, irritation of the receptors of one organ leads to changes in the work of another.
• Viscero-sensory. Irritation leads to changes in the sensitivity of the skin.
• Soma-visceral. Irritation leads to a change in the work of internal organs.

As a result, we can say that the topic, as well as the features of the autonomic nervous system, are very extensive, if you delve into medical terms. However, we do not need this at all.

To deal with violation autonomic dysfunction, you need to follow certain rules and understand the simple essence of the work, which we have already talked about many times. Everything else needs to be known exclusively to specialists.

The above diagram of the autonomic nervous system will help you understand and understand which department is disrupted.

autonomic nervous system- an important part of the entire system of the human body. The main function is to ensure the normal functioning of all internal organs. Thanks to this system, the human body functions normally. It consists of two sections: the sympathetic and parasympathetic divisions of the autonomic nervous system.

It is almost impossible to control the autonomic nervous system. All processes in the sympathetic and parasympathetic nervous division occur on their own without direct involvement person. The article will help you learn more about the parasympathetic and sympathetic department, what it is and how it affects the body.

Autonomic nervous system: sympathetic and parasympathetic nervous system

First you need to figure out what it is and what departments it consists of. The nervous system, as many school curriculum, consists of nerve cells and processes, the sympathetic and parasympathetic divisions of the nervous system.

There are two divisions of the autonomic nervous system:

• Peripheral.
• Central.

The central part of the nervous system is the most important. With its help, the smooth operation of the internal organs of the human body is carried out. The department never rests and regulates constantly.

The peripheral division is further divided by the parasympathetic and sympathetic divisions. The parasympathetic and sympathetic divisions work together. It all depends on what the body needs for a given period of time. Some of the departments in this case will work harder. It is this work of the sympathetic and parasympathetic departments that helps him adapt to different conditions. If the sympathetic and parasympathetic departments function well, then this helps to avoid the negative consequences of acclimatization and other troubles.

Consider the functions of the nervous system:

• ensuring the smooth operation of internal organs with the help of the sympathetic and parasympathetic departments;
• maintenance of physical and psychological processes by parasympathetic.

When playing sports, the nervous autonomic system will help maintain a normal balance of blood pressure and good blood circulation. And during rest, the nervous system helps to normalize blood pressure readings and calm the body. Thus, the well-being of a person will not cause discomfort.

Sympathetic division of the ANS

Sympathetic system needed to control the processes of the spinal cord, metabolism and other internal organs. The sympathetic system is represented by fibers of nerve tissues. Thus, uninterrupted control over all processes of the sympathetic nervous department is ensured.

The sympathetic nervous division is located only in the spinal cord, in contrast to the parasympathetic. Wraps both sides. At the same time, they are interconnected and resemble a bridge. This arrangement of the sympathetic nerve section helps to ensure a high-quality and quick response of the body to irritations of nerve cells. The sympathetic nervous region envelops the cervical, thoracic, lumbar and sacral regions. Thanks to this, a constant working process of the internal organs is ensured, and all the necessary vital functions of the sympathetic nervous department are supported.

In the cervical region, the carotid artery is under control, in the thoracic region, the lungs and heart are under control. The spinal cord and brain are connected to each other and give the necessary signals. Thanks to the work of the sympathetic nervous department, a person is able to adequately perceive the world around him and adapt to different habitats.

The work of the sympathetic nervous department must be controlled. In case of some failure, it is recommended to consult a doctor for further examinations of the sympathetic nerve section.

If the problem of the sympathetic nervous department is insignificant, then you can use drug treatment.

The sympathetic nervous section ensures the normal functioning of the arteries and performs a number of other functions:

1. Increase in blood sugar;
2. pupil dilation;
3. Ensuring the normal functioning of the metabolism;
4. Adrenalin;
5. sweating;
6. Salivation control;
7. Increase in cholesterol;
8. Decoding VNS;
9. Change in muscle physiology;
10. Bronchial expansion.

Any person should know what function is performed in the spine with the help of parasympathetic nerves and the sympathetic system.

The sympathetic nervous department monitors pupillary dilation and salivation in the cervical spine. The thoracic region is responsible for the expansion of the bronchi and a decrease in appetite. Adrenaline is produced by the sympathetic nerve section in the lumbar region. Relaxation of the bladder - in the sacral zone.

parasympathetic system

In the parasympathetic system, all processes occur in reverse. In the cervical region, the pupils constrict when the parasympathetic region is excited. Strengthening digestion and narrowing of the bronchi - the thoracic region of the parasympathetic system. Irritation of the gallbladder - lumbar. Bladder contraction - sacral region.

Differences between sympathetic and parasympathetic divisions?

Sympathetic and parasympathetic divisions can work together, but provide different effects on the body.

1. Sympathetic fibers are small and short. Parasympathetic have an elongated shape.
2. Sympathy is enveloped in gray branches. There is no such thing in the parasympathetic system.

Improper functioning of the metasympathetic system can exacerbate certain diseases, such as: nocturnal enuresis, autonomic failure, reflex dystrophy and others. If you suspect one of them, you should consult a doctor for help immediately.

Treatment of diseases of the nervous system

The doctor prescribes the necessary treatment after the cause of the disease is identified and where it occurs to a greater extent in the sympathetic nervous department.

Such diseases are treated with the help of medicines:

• antidepressants;
• anticonvulsants;
• neuroleptics.

Parasympathetic division of the nervous system

It is possible that the parasympathetic division plays an important role in metabolism. But this fact about the parasympathetic system has not been fully proven by scientists to date. Some argue that the parasympathetic department is located not only in the spinal cord, but also goes to the walls of the body. To control the parasympathetic system, you should contact a neurologist.

The parasympathetic department performs its function, being in the sacral region of the spinal cord and brain.

Functions of the parasympathetic nervous system:

1. Have control over the pupils;
2. Tearing of the parasympathetic department;
3. Salivation;
4. The parasympathetic system affects the functioning of the internal organs of the human body.

Diseases such as diabetes mellitus, Parkinson's disease, Raynaud's syndrome, can be caused as a result of malfunctioning of the parasympathetic division.

Departments of the nervous system

Central department. This department as if "scattered" throughout the brain. Represents segments that play an important role in the normal life of a person. The central nervous system includes not only the brain, but also the spinal cord. It is sometimes necessary to check the functioning of the nervous system. A neurologist, neurosurgeon and traumatologist can help with this. Diagnostics is carried out using CT, MRI and x-rays.

The hypothalamus is an integral part of the structure of the brain, which is located at the base. Thanks to this structure, the function of lactation is performed in female representatives, blood circulation, respiration, and digestive organs are controlled. The work of controlling body temperature and perspiration is also performed. The hypothalamus is responsible for sexual desire, emotions, growth, pigmentation.

Sweating, vasodilation and other actions are caused by irritation of the hypothalamus.

The hypothalamus distinguishes two zones: ergotropic and trophotropic. The activity of the trophotropic zone is associated with rest and maintenance of synthesis. Influence gives through the parasympathetic department. Increased sweating, salivation, lowering blood pressure - all this is due to irritation of the hypothalamus in the parasympathetic region. Thanks to the ergotropic system, the brain receives a signal about a change in climate and a period of adaptation begins. At the same time, some people noticed on themselves how blood pressure rises, dizziness begins and other processes occur due to the parasympathetic department.

Reticular formation

This nervous system envelops the entire surface of the brain, forming a semblance of a grid. This convenient location allows you to monitor every process in the body. Thus, the brain will always be ready to work.

But there are also separate structures that are responsible for only one work of the body. For example, there is a center that takes responsibility for breathing. If this center is damaged, independent breathing is considered impossible and third-party assistance is required. Similar to this center, there are others (swallowing, coughing, etc.).

conclusions

All centers of the nervous system are interconnected. Only the joint work of the parasympathetic and sympathetic departments will ensure the normal functioning of the body. Dysfunction of at least one of the departments can lead to serious diseases not only of the nervous system, but also of the respiratory, motor and cardiovascular systems. Bad job The parasympathetic and sympathetic department is connected with the fact that the necessary flow does not pass through the nerve impulses, which irritates the nerve cells and does not give a signal to the brain to perform any action. Any person should understand what functions the parasympathetic and sympathetic department carries. This is necessary in order to independently try to determine which area does not perform the work in full force, or does not perform it at all.

The autonomic nervous system (ANS, ganglionic, visceral, organ, autonomic) is a complex mechanism that regulates the internal environment in the body.

The subdivision of the brain into functional elements is described rather conditionally, since it is a complex, well-oiled mechanism. The ANS, on the one hand, coordinates the activity of its structures, and on the other hand, it is exposed to the influence of the cortex.

General information about VNS

The visceral system is responsible for many tasks. The higher nerve centers are responsible for the coordination of the ANS.

The neuron is the main structural unit of the ANS. The path along which impulse signals travel is called a reflex arc. Neurons are necessary for conducting impulses from the spinal cord and brain to somatic organs, glands and smooth muscle tissue. An interesting fact is that the heart muscle is represented by striated tissue, but it also contracts involuntarily. Thus, autonomic neurons regulate the heart rate, the secretion of endocrine and exocrine glands, intestinal peristaltic contractions, and perform many other functions.

The ANS is subdivided into the parasympathetic and parasympathetic subsystems (SNS and PNS, respectively). They differ in the specifics of innervation and the nature of the reaction to substances that affect the ANS, but at the same time they closely interact with each other - both functionally and anatomically. The sympathetic is stimulated by adrenaline, the parasympathetic by acetylcholine. The first is inhibited by ergotamine, the last by atropine.

Functions of the ANS in the human body

The tasks of the autonomous system include the regulation of all internal processes occurring in the body: the work of somatic organs, blood vessels, glands, muscles, and sensory organs.

The ANS maintains the stability of the human internal environment and the realization of such vital important functions like breathing, circulation, digestion, temperature regulation, metabolic processes, excretion, reproduction and others.

The ganglionic system participates in adaptive-trophic processes, that is, it regulates metabolism according to external conditions.

Thus, the vegetative functions are as follows:

• support of homeostasis (invariance of the environment);
• adaptation of organs to various exogenous conditions (for example, in the cold, heat transfer decreases, and heat production increases);
• vegetative realization of mental and physical activity of a person.

The structure of the VNS (how it works)

Consideration of the structure of the ANS by levels:

suprasegmental

It includes the hypothalamus, the reticular formation (waking and falling asleep), the visceral brain (behavioral reactions and emotions).

The hypothalamus is a small layer of the medulla. It has thirty-two pairs of nuclei that are responsible for neuroendocrine regulation and homeostasis. The hypothalamic region interacts with the cerebrospinal fluid circulation system, since it is located near the third ventricle and subarachnoid space.

In this area of ​​the brain, there is no glial layer between neurons and capillaries, which is why the hypothalamus immediately responds to changes in the chemical composition of the blood.

The hypothalamus interacts with the organs of the endocrine system by sending oxytocin and vasopressin, as well as releasing factors, to the pituitary gland. The visceral brain is associated with the hypothalamus (psycho-emotional background in hormonal changes) and the cerebral cortex.

So, the work of this important area is dependent on the cortex and subcortical structures. The hypothalamus is the highest center of the ANS, which regulates different kinds metabolism, immune processes, maintains the stability of the environment.

Segmental

Its elements are localized in the spinal segments and basal ganglia. This includes SMN and PNS. Sympathy includes the core of Yakubovich (regulation of the muscles of the eye, constriction of the pupil), the nuclei of the ninth and tenth pairs of cranial nerves (the act of swallowing, providing nerve impulses to the cardiovascular and respiratory systems, the gastrointestinal tract).

The parasympathetic system includes centers located in the sacral spinal region (innervation of the genital and urinary organs, rectal region). From the centers of this system come fibers reaching the target organs. This is how each specific organ is regulated.

The centers of the cervicothoracic region form the sympathetic part. From the nuclei of the gray matter come short fibers that branch out in the organs.

Thus, sympathetic irritation manifests itself everywhere - in different parts of the body. Acetylcholine is involved in sympathetic regulation, and adrenaline is involved in the periphery. Both subsystems interact with each other, but not always antagonistically (sweat glands are innervated only sympathetically).

Peripheral

It is represented by fibers entering peripheral nerves and ending in organs and vessels. Particular attention is paid to the autonomic neuroregulation of the digestive system - an autonomous formation that regulates peristalsis, secretory function etc.

Vegetative fibers, unlike the somatic system, are devoid of myelin sheath. Because of this, the speed of pulse transmission through them is 10 times less.

sympathetic and parasympathetic

Under the influence of these subsystems are all organs, except for the sweat glands, blood vessels and the inner layer of the adrenal glands, which are innervated only sympathetically.

The parasympathetic structure is considered more ancient. It contributes to the creation of stability in the work of organs and conditions for the formation of an energy reserve. The sympathetic department changes these states depending on the function performed.

Both departments work closely together. When certain conditions occur, one of them is activated, and the second is temporarily inhibited. If the tone of the parasympathetic division predominates, parasympathotonia occurs, the sympathetic - sympathotonia. The former is characterized by a state of sleep, while the latter is characterized by heightened emotional reactions (anger, fear, etc.).

command centers

Command centers are located in the cortex, hypothalamus, brain stem, and lateral spinal horns.

Peripheral sympathetic fibers originate from the lateral horns. The sympathetic trunk stretches along the spinal column and unites twenty-four pairs of sympathetic nodes:

• three cervical;
• twelve chest;
• five lumbar;
• four sacral.

The cells of the cervical node form the nerve plexus of the carotid artery, the cells of the lower node form the superior cardiac nerve. Thoracic nodes provide innervation of the aorta, broncho-pulmonary system, abdominal organs, lumbar - organs in the small pelvis.

The mesencephalic region is located in the midbrain, in which the nuclei of the cranial nerves are concentrated: the third pair is the nucleus of Yakubovich (mydriasis), the central posterior nucleus (innervation of the ciliary muscle). Medulla otherwise called the bulbar department, nerve fibers which are responsible for the processes of salivation. Also here is the vegetative nucleus, which innervates the heart, bronchi, gastrointestinal tract and other organs.

Nerve cells of the sacral level innervate urinary organs, rectal gastrointestinal tract.

In addition to these structures, a fundamental system is distinguished, the so-called "base" of the ANS - this is the hypothalamic-pituitary system, the cerebral cortex and the striatum. The hypothalamus is a kind of "conductor", which regulates all underlying structures, controls the work of the endocrine glands.

VNS Center

The leading regulatory link is the hypothalamus. Its nuclei are connected with the bark telencephalon and the lower divisions of the trunk.

Role of the hypothalamus:

• close relationship with all elements of the brain and spinal cord;
• implementation of neuroreflex and neurohumoral functions.

The hypothalamus is permeated with a large number of vessels through which protein molecules penetrate well. Thus, this is a rather vulnerable area - against the background of any diseases of the central nervous system, organic damage, the work of the hypothalamus is easily disrupted.

The hypothalamic region regulates falling asleep and waking up, many metabolic processes, hormonal levels, the work of the heart and other organs.

Formation and development of the central nervous system

The brain is formed from the anterior wide part of the brain tube. Its posterior end, as the fetus develops, is converted into the spinal cord.

At the initial stage of formation, with the help of constrictions, three brain bubbles are born:

• diamond-shaped - closer to the spinal cord;
• average;
• front.

The canal, located inside the anterior part of the brain tube, changes its shape and size as it develops, and is modified in the cavity - the ventricles of the human brain.

Allocate:

• lateral ventricles - cavities of the telencephalon;
• 3rd ventricle - represented by the cavity of the diencephalon;
• - cavity of the midbrain;
• The 4th ventricle is the cavity of the posterior and medulla oblongata.

All ventricles are filled with cerebrospinal fluid.

ANS dysfunctions

When the ANS malfunctions, a variety of disorders are observed. Most of pathological processes entails not the loss of a particular function, but increased nervous excitability.

Problems in some departments of the ANS can be transferred to others. The specificity and severity of symptoms depend on the affected level.

Damage to the cortex leads to the emergence of vegetative, psycho-emotional disorders, tissue malnutrition.

The reasons are varied: trauma, infection, toxic effects. At the same time, patients are restless, aggressive, exhausted, they have increased sweating, fluctuations in heart rate and pressure.

When the limbic system is irritated, vegetative-visceral attacks appear (gastrointestinal, cardiovascular, etc.). Psycho-vegetative and emotional disorders develop: depression, anxiety, etc.

With damage to the hypothalamic area (neoplasms, inflammation, toxic effects, trauma, circulatory disorders), vegetative-trophic (sleep disorders, thermoregulatory function, stomach ulcers) and endocrine disorders develop.

Damage to the nodes of the sympathetic trunk leads to impaired sweating, hyperemia of the cervicofacial region, hoarseness or loss of voice, etc.

Dysfunction of the peripheral parts of the ANS often causes sympathalgia (painful sensations of various localization). Patients complain of a burning or pressing nature of pain, often there is a tendency to spread.

Conditions may develop in which the functions of various organs are impaired due to the activation of one part of the ANS and the inhibition of another. Parasympathotonia is accompanied by asthma, urticaria, runny nose, sympathotonia - migraine, transient hypertension, panic attacks.