The autonomic nervous system, also known as the autonomic nervous system, is part of the nervous system human, which regulates internal processes, controls almost all internal organs, and is also responsible for human adaptation to new living conditions.

Main functions of the autonomic nervous system

Trophotropic - maintaining homeostasis (constancy internal environment organism regardless of changes in external conditions). This function helps maintain the normal functioning of the body in almost any conditions.

Within its framework, the autonomic nervous system regulates cardiac and cerebral circulation, blood pressure, respectively body temperature, organic blood parameters (pH level, sugar, hormones, etc.), the activity of the glands of external and internal secretion, tone lymphatic vessels.

Ergotropic - ensuring normal physical and mental types body activity depending on specific conditions human existence at a specific point in time.

In simple words, this function allows the autonomic nervous system to mobilize energetic resources the body to preserve human life and health, which is necessary, for example, in an extreme situation.

At the same time, the functions of the autonomic nervous system also extend to the accumulation and “redistribution” of energy depending on a person’s activity at a particular moment in time, that is, it ensures normal rest of the body and accumulation of strength.

Depending on the functions performed, the autonomic nervous system is divided into two sections - parasympathetic and sympathetic, and anatomically - into segmental and suprasegmental.

The structure of the autonomic nervous system. Click on the image to view in full size.

Suprasegmental division of the ANS

This is, in fact, the dominant department, giving commands to the segmental one. Depending on the situation and conditions external environment it “turns on” the parasympathetic or sympathetic department. Above segmental department The human autonomic nervous system includes the following functional units:

1. Reticular formation of the brain. It houses the respiratory and activity control centers. of cardio-vascular system, responsible for sleep and wakefulness. It is a kind of “sieve” that controls impulses entering the brain, primarily during sleep.
2. Hypothalamus. Regulates the relationship between somatic and vegetative activities. It contains the most important centers that maintain constant and normal indicators for the body: body temperature, heart rate, blood pressure, hormonal levels, as well as controlling feelings of satiety and hunger.
3. Limbic system . This center controls the appearance and extinction of emotions, regulates the daily routine - sleep and wakefulness, and is responsible for preserving the species, eating and sexual behavior.

Since the centers of the suprasegmental part of the autonomic nervous system are responsible for the appearance of any emotions, both positive and negative, it is quite natural that to cope with the disorder autonomic regulation It is quite possible to control emotions by yourself:

• weaken or turn in a positive direction the course of various pathologies;
• dock pain syndrome, calm down, relax;
• independently, without any medicines cope not only with psycho-emotional, but also physical manifestations.

This is confirmed by statistical data: approximately 4 out of 5 patients diagnosed with VSD are capable of self-healing without the use of auxiliary medications or therapeutic procedures.

Apparently, a positive attitude and self-hypnosis help the autonomic centers independently cope with their own pathologies and relieve a person from unpleasant manifestations vegetative-vascular dystonia.

Segmental department of the VNS

The segmental vegetative department is controlled by the suprasegmental one and is a kind of “executive organ”. Depending on the functions performed, the segmental department of the autonomic nervous system is divided into sympathetic and parasympathetic.

Each of them has a central and peripheral part. The central section consists of sympathetic nuclei, located in the immediate vicinity of the spinal cord, and parasympathetic cranial and lumbar nuclei. The peripheral department includes:

1. branches, nerve fibers, autonomic branches emerging from the spinal cord and brain;
2. autonomic plexuses and their nodes;
3. sympathetic trunk with its nodes, connecting and internodal branches, sympathetic nerves;
4. pair end units sympathetic division autonomic nervous system.

In addition, some individual organs“equipped” with their own plexuses and nerve endings, carry out their regulation both under the influence of the sympathetic or parasympathetic department, and autonomously. These organs include the intestines, bladder and some others, and their nerve plexuses are called the third metasympathetic division of the autonomic nervous system.

The sympathetic department is represented by two trunks running along the entire spine - left and right, which regulate the activity of paired organs on the corresponding side. The exception is the regulation of the activity of the heart, stomach and liver: they are controlled by two trunks simultaneously.

The sympathetic department is in most cases responsible for exciting processes; it dominates when a person is awake and active. In addition, it is he who “takes responsibility” for controlling all functions of the body in extreme or stressful situation- mobilizes all the forces and all the energy of the body for decisive action in order to preserve vital activity.

The parasympathetic autonomic nervous system acts opposite to the sympathetic one. It does not excite, but inhibits internal processes, with the exception of those occurring in the organs digestive system. It provides regulation when the body is at rest or in sleep, and it is due to its work that the body manages to rest and gain strength, stock up on energy.

Sympathetic and parasympathetic divisions

The autonomic nervous system controls all internal organs, and it can both stimulate their activity and relax them. The sympathetic nervous system is responsible for stimulation. Its main functions are as follows:

1. narrowing or toning of blood vessels, accelerating blood flow, increasing blood pressure, body temperature;
2. increased heart rate, organization of additional nutrition of certain organs;
3. slower digestion, decreased intestinal motility, decreased production of digestive juices;
4. contracts sphincters, reduces gland secretion;
5. dilates the pupil, activates short term memory, improves attention.

Unlike the sympathetic, the parasympathetic autonomic nervous system “turns on” when the body is resting or sleeping. She slows down physiological processes in almost all organs, concentrates on the function of storing energy and nutrients. It affects organs and systems as follows:

1. reduces tone, dilates blood vessels, due to which the level of blood pressure and the speed of blood movement throughout the body decrease, metabolic processes slow down, and body temperature decreases;
2. the heart rate decreases, the nutrition of all organs and tissues in the body decreases;
3. digestion is activated: actively produced digestive juices, intestinal motility increases - all this is necessary for energy accumulation;
4. gland secretion increases, sphincters relax, resulting in cleansing of the body;
5. the pupil narrows, attention is distracted, the person feels drowsiness, weakness, lethargy and fatigue.

The normal functions of the autonomic nervous system are maintained mainly due to a peculiar balance between the sympathetic and parasympathetic departments. Its violation is the first and main impetus for the development of neurocirculatory or vegetative-vascular dystonia.

Centers of the autonomic nervous system

Anatomical formations related to the autonomic nervous system. Syndrome of damage to the lateral horns of the spinal cord. Horner's syndrome.

Cauda equina syndrome (partial, complete).

Horse tail (cauda equina)(roots from spinal cord segments L II - S Y) asymmetry of symptoms

· peripheral paralysis of the lower extremities;

· dysfunction pelvic organs By peripheral type;

· disturbance of all types of sensitivity of the peripheral type on the lower extremities and in the perineum;

radicular pain in the legs

Segmental centers:

n Mesencephalic division - accessory nucleus (Yakubovich) and unpaired median nucleus (III pair).

n Bulbar department : 1) superior salivary nucleus (VII pair), 2) inferior salivatory nucleus (IX pair) and 3) dorsal nucleus (X pair).

n Thoracolumbar region - intermediate-lateral nuclei of spinal cord segments from the 8th cervical to the 3rd lumbar inclusive (C8 - L3).

n Sacral department - intermediate-lateral nuclei of spinal cord segments (S2-S4)

n Reticular formation - respiratory and vasomotor centers, centers of cardiac activity, regulation of metabolism, etc.).

n Cerebellum - trophic centers.

n Hypothalamus - main subcortical center -

(metabolism level, thermoregulation).

n Striatum - unconditioned reflex regulation vegetative functions.

n The highest center for the regulation of vegetative and somatic functions and their coordination is cerebral cortex .

Differential characteristics of the main parts of the autonomic nervous system

Signs	Parts
sympathetic	parasympathetic
Main functions	ergotropic- aimed at vegetative-metabolic support of various forms of adaptive purposeful behavior (mental and physical activity, implementation of biological motivations - food, sexual, motivations of fear and aggression).	trophotropic– aimed at maintaining the dynamic constancy of the internal environment of the body (its physicochemical, biochemical, enzymatic, humoral and other constants).
excitatory transmitter	adrenalin	acetylcholine
brake mediator	ergotamine	atropine
other name	adrenergic	cholinergic
with predominance of excitability	rapid pulse, tachypnea, bright eyes and dilated pupils, tendency to arterial hypertension, chilliness, weight loss, constipation, anxiety, increased performance, especially in evening time, initiative with reduced concentration, etc.	slow heart rate, decreased blood pressure, tendency to faint, obesity, narrow pupils, apathy, indecisiveness, performance is better in the morning
Localization in the hypothalamus	posterior sections	anterior sections

* autonomic (sympathetic and parasympathetic neurons ) located in the lateral horns and are visceromotor cells;

* lateral horns of the spinal cord on level C YIII - Th I – cilio-spinal center.

The axons of the bodies of sympathetic neurons as part of the anterior roots leave the spinal canal and, in the form of a connecting branch, penetrate the first thoracic and lower cervical nodes of the sympathetic trunk. The fibers, without interruption, end at the cells of the superior cervical sympathetic ganglion. Postganglionic fibers weave around the wall of the inner carotid artery, along which they enter the cranial cavity, and then along ophthalmic artery reach the orbit and end in smooth muscle, the contraction of which causes the pupil to dilate. In addition, sympathetic fibers contact the muscle that dilates the palpebral fissure and the smooth muscles of the orbital tissue. When the impulses traveling along the sympathetic fibers are turned off, a triad of symptoms occurs ( Claude-Bernard-Horner syndrome): constriction of the pupil (miosis), constriction palpebral fissure(ptosis), retraction eyeball(enophthalmos);

* border pillar nodes- pain of a burning nature, without precise boundaries, periodically exacerbating, paresthesia, hypoesthesia or hyperesthesia, pronounced disorders of pilomotor, vasomotor, secretory and trophic innervation.

* Lesions are of particular importance four cervical sympathetic nodes: upper, middle, additional and stellate. Defeat upper cervical node manifests itself mainly as a violation of the sympathetic innervation of the eye (Bernard-Horner syndrome). The pain spreads to half the face and even the entire half of the torso. Defeat stellate node manifested by pain and sensitivity disorders in upper limb And upper section chest. In case of defeat:

* upper thoracic nodes pain and skin manifestations, combined with vegetative-visceral disorders (difficulty breathing, tachycardia, pain in the heart). Usually the manifestations are more pronounced on the left.

* lower thoracic and lumbar nodes manifests itself as a violation of the cutaneous-vegetative innervation of the lower part of the body, legs and autonomic-visceral disorders of the organs abdominal cavity;

* ganglia - pterygopalatine, ciliary, ear, submandibular and sublingual.

22. Olfactory nerve(I): symptoms of damage. Visual path(II): symptoms of damage at various levels.

I pair – OLfactory NERVE.

The cell of the first neuron (receptors) of the olfactory pathway is located in the mucous membrane of the upper nasal passage in the region. superior concha and nasal septum. The primary olfactory centers are the olfactory triangle, the septum pellucida, and the substantia perforatum. The cortical olfactory center is the hippocampal gyrus in the temporal lobe.

For humans, the acuity of smell is not significant, but reducing it ( hyposmia) or lack thereof (anosmia) is often accompanied by a decrease taste sensations and as a consequence of this - decreased appetite. A decreased sense of smell may be a congenital feature, but it can occur when the olfactory pathways are damaged, as well as from diseases of the nasal cavity. In some cases, there is an exacerbation of the sense of smell - hyperosmia for example, in some forms of hysteria and sometimes in cocaine addicts, dysosmia(perversions of smell) – during pregnancy, in case of poisoning chemicals, with psychosis. When irritating the cortical end of the olfactory analyzer, i.e. temporal region arise olfactory hallucinations . In particular, seizure may begin with precursors in the form of a sensation of some smell (olfactory aura).

Physiological and anatomical features of the autonomic nervous system. The autonomic nervous system (autonomous) is part of the nervous system that innervates blood vessels and internal organs, coordinating their work and regulating metabolic and trophic processes (thus maintaining homeostasis of the body). It is divided into central and peripheral, and includes two sections: sympathetic and parasympathetic. The central autonomic nervous system includes clusters nerve cells, forming nuclei (centers) that are located in the brain and spinal cord. The peripheral section includes autonomic fibers, autonomic nodes (ganglia), and autonomic nerve endings.

Physiological feature The autonomic nervous system is the following: 1) it is part of the holistic reaction of the body; 2) has a low speed of nerve signal transmission; 3) is not subject to voluntary control by the brain; 4) has three types of influences on the work of organs: 5) triggering (starts the work of organs that are not working properly); 6) corrective (strengthens or weakens the functioning of organs); 7) adaptive-trophic (includes the metabolic system aimed at restoring homeostasis).

Anatomical feature autonomic nervous system is that the neurons that control muscles internal organs and glands, lie outside the central part of the autonomic nervous system and form clusters - ganglia. Thus, there is an additional link between the central structures of the autonomic nervous system and the effectors. The section of fiber running from the central neurons to the ganglion is called a preganglionic fiber, and the section of fiber running from the ganglion to the effector is called a postganglionic fiber. The autonomic reflex arc consists of three links: receptor (sensitive neurons are located in organs, and their axon as part of the dorsal root enters the spinal cord); associative (the intercalary neuron is located in the lateral horns of the spinal cord and transmits a signal to the autonomic ganglion through the preganglionic fiber); efferent (the motor neuron is located in the autonomic ganglion, and through the postganglionic fiber transmits excitation to the working organ).

The sympathetic and parasympathetic divisions of the nervous system have a number of differences. The preganglionic fibers of the sympathetic division emerge from the thoracic and lumbar sections of the spinal cord, the ganglia are located next to the central section, and long postganglionic fibers extend from them. Acetylcholine is involved in the transmission of information from the preganglionic fiber to the ganglion, but the main neurotransmitter that affects the effectors is norepinephrine. Activation of the sympathetic department causes ergotropic effects: the excitability and conductivity of organ systems increases, metabolic processes, breathing and heart rate increase, i.e. the body adapts to intense activity, the body's defenses are activated. Long preganglionic fibers of the parasympathetic region begin in the trunk and sacral parts of the spinal cord, and the ganglia are located near the effectors. The neurotransmitter acetylcholine takes part in transmitting information from the preganglionic neuron to the ganglion and from the postganglionic neuron to the working organ. Activation of the parasympathetic department creates conditions for rest and recuperation. Trophotropic processes intensify: synthesis increases digestive enzymes and, the secretion of the digestive glands increases. There is a decrease in heart rate and constriction of the pupils.

Normally, between the sympathetic and parasympathetic divisions there is unstable equilibrium, the shifts of which are caused by the action of stimuli from the external and internal environment. The action of both departments on the same organs most often leads to opposite effects, i.e. they work as antagonists. In some cases, synergism is observed in the work of both departments: during digestion, the protein composition of saliva increases (the action of the sympathetic department) and its quantity increases (the action of the parasympathetic department). Almost complete shutdown of the sympathetic department is not dangerous for the functioning of the body, but disturbances in the functioning of the parasympathetic department can lead to serious consequences: regulation of blood supply, temperature regulation of the body is disrupted, fatigue quickly sets in, i.e. a person in this state does not adapt well to change environment.

Higher autonomic centers brain Central regulation of the functions of the autonomic nervous system is carried out with the participation of various parts of the brain. Brain stem contains vital centers such as respiratory, vasomotor, cardiac centers, etc. The nucleus of the vagus nerve sends its axons to most of the internal organs, innervating both smooth muscle and glands (for example, salivary glands). Midbrain ensures the sequence of reactions of the act of eating and breathing. The main role of the descending part of the reticular formation of the trunk is to increase the activity of nerve centers associated with autonomic functions. The reticular formation has a tonic effect on them, ensuring a high level of their activity. At the same time, the reticular formation is able to regulate the activity of the hypothalamus. The monoaminergic system of the brainstem (noradrenergic neurons of the locus coeruleus, dopaminergic neurons of the midbrain and serotonergic neurons in the nuclei of the median raphe) is involved in autonomic support emotional states, sleep-wake cycle and modulation of higher mental functions. Cerebellum, Having extensive afferentation from the external environment, it participates in the regulation of the autonomic support of any muscular activity, and contributes to the activation of all the body’s reserves for performing muscular work. Striatum participates in the unconditioned reflex regulation of autonomic functions (salivation and lacrimation, sweating, etc.) Limbic system- the “visceral brain” corrects the vegetative support of nutritional, sexual, defensive and other forms of behavior, as well as various emotional states. This correction is carried out by modulating the activity of the autonomic nervous system, mainly with the participation of the hypothalamus, which is the center for the integration of motor, endocrine and emotional components of complex reactions of adaptive behavior, the center for the regulation of homeostasis and metabolism. Hippocampus and amygdala are also higher parasympathetic centers that realize their effect through the hypothalamus. The amygdala contains neurons that increase the activity of the sympathetic nervous system. They are activated by negative emotions. For example, under these conditions, coronary blood flow decreases, blood pressure increases, and the content of red blood cells and hemoglobin in the blood decreases. Therefore, fear, rage, and aggressiveness, which are initiated when the neurons of the amygdala are excited, are often the cause of severe pathology of the cardiovascular system. Thalamus- a structure that has extensive connections with the somatic nervous system and the reticular formation. Intrathalamic connections ensure the integration of complex motor reactions with autonomic processes.

Bark can have a direct and indirect effect on the functioning of internal organs, which is carried out with the participation of autonomic centers located in various parts of the cortex. Potentially, the cortex can exercise any influence on vegetative functions, but it uses its capabilities in case emergency. Along with the hypothalamus and other components of the limbic system, the cortex is capable of long-term regulation of the work of internal organs (based on the development of numerous autonomic reflexes), which contributes to the successful adaptation of the body to new conditions of existence, including when performing accounting, work and household activities. The ability of the cortex to exert not only an exciting, but also an inhibitory influence on the subcortical autonomic centers gives a person the opportunity to control his emotions, significantly expanding the boundaries of social and biological adaptation.

The hypothalamus as the highest center for the regulation of autonomic functions. As noted above, the hypothalamus contains neurons responsible for regulating the activity of the sympathetic and parasympathetic centers of the brain stem and spinal cord, as well as for the secretion of pituitary hormones, thyroid gland, adrenal glands and gonads. Thanks to this, the hypothalamus participates in the regulation of the activity of all internal organs, in the regulation of such integrative processes as energy and substance metabolism, thermoregulation, as well as the formation of biological motivations of various modalities (for example, food, drink and sexual), thanks to which the behavioral activity of the body is organized, aimed at satisfying relevant biological needs. It was already noted above that, according to the hypothesis of W. Hess, the nuclei of the anterior and partially middle hypothalamus are considered as higher pairs sympathetic centers, or trophotropic zones, while the nuclei of the posterior (and partly middle) hypothalamus are like higher sympathetic centers, or ergotropic zones. On the other hand, there is an idea of ​​diffuse localization of neurons that regulate the activity of sympathetic (or parasympathetic) neurons - in each center responsible for regulating the activity of the corresponding internal organ or integrative process, there are both types of neurons. It is now known that the hypothalamus regulates the activity of the cardiovascular system; activity of blood coagulation and anticoagulation systems; activity of the body’s immune system (together with the thymus gland); external respiration, including coordination of pulmonary ventilation, with the activity of the cardiovascular system and with somatic reactions; motor and secretory activity of the digestive tract; water-salt metabolism, ionic composition, extracellular fluid volume and other indicators of homeostasis; intensity of urine formation; protein, carbohydrate and fat metabolism; main and general exchange, as well as thermoregulation. The hypothalamus plays an important role in the regulation of eating behavior. The existence of two interacting centers in the hypothalamus has been established: hunger (lateral nucleus of the hypothalamus) and satiety (ventromedial nucleus of the hypothalamus). Electrical stimulation of the hunger center provokes the act of eating in a well-fed animal, while stimulation of the satiety center interrupts food intake. The destruction of the hunger center causes a refusal to consume food (aphagia) and water, which often leads to the death of the animal. Electrical stimulation of the lateral nucleus of the hypothalamus increases the secretion of the salivary and gastric glands, bile, insulin, and enhances the motor activity of the stomach and intestines. Damage to the satiety center increases food intake (hyperphagia). Almost immediately after such an operation, the animal begins to eat a lot and often, which leads to hypothalamic obesity. When food is restricted, body weight decreases, but as soon as the restrictions are removed, hyperphagia reappears, decreasing only with the development of obesity. These animals also showed increased pickiness when choosing food, preferring the most tasty. Obesity following damage to the ventromedial nucleus of the hypothalamus is accompanied by anabolic changes: glucose metabolism changes, the level of cholesterol and triglycerides in the blood increases, the level of oxygen consumption and amino acid utilization decreases. Electrical stimulation of the ventromedial hypothalamus reduces the secretion of the salivary and gastric glands, insulin, and gastric and intestinal motility. Thus, we can conclude that the lateral hypothalamus is involved in the regulation of metabolism and internal secretion, and the ventromedial hypothalamus has an inhibitory effect on it.

The role of the hypothalamus in the regulation of eating behavior. Normally, blood sugar is one of the important (but not the only) factors in eating behavior. Its concentration very accurately reflects the energy need of the body, and the difference in its content in arterial and venous blood is closely related to the feeling of hunger or satiety. The lateral nucleus of the hypothalamus contains glucoreceptors (neurons with glucose receptors in their membranes), which are inhibited when blood glucose levels increase. It has been established that their activity in to a large extent determined by glucoreceptors of the ventromedial nucleus, which are primarily activated by glucose. Hypothalamic glucoreceptors receive information about glucose levels in other parts of the body. This is signaled by peripheral glucoreceptors located in the liver, carotid sinus, wall of the gastrointestinal tract. Thus, the glucoreceptors of the hypothalamus, integrating information received through the nervous and humoral pathways, are involved in the control of food intake. Numerous data have been obtained on the participation of various brain structures in controlling food intake. Aphagia(refusal to eat) and adipsia(refusal of water) are observed after damage to the globus pallidus, red nucleus, tegmentum of the midbrain, substantia nigra, temporal lobe, and amygdala. Hyperphagia(gluttony) develops after damage frontal lobes, thalamus, central gray matter of the midbrain. Despite the innate nature food reactions, numerous data show that conditioned reflex mechanisms play an important role in the regulation of food intake. Many factors are involved in the regulation of eating behavior. The effect of the sight, smell and taste of food on appetite is well known. The degree of filling of the stomach also affects appetite. The dependence of food intake on ambient temperature is well known: low temperature stimulates food intake, high - inhibits. Finite adaptive effect all mechanisms involved in eating behavior, consists of taking an amount of food balanced in calorie content with the energy consumed. This ensures constant body weight.

The role of the hypothalamus in the regulation of body temperature. At a level of 36.6° C, a person’s body temperature is maintained with very high accuracy, down to tenths of a degree. The anterior hypothalamus contains neurons whose activity is sensitive to changes in the temperature of this region of the brain. If the temperature of the anterior hypothalamus is artificially raised, the animal experiences an increase in respiratory rate, dilation of peripheral blood vessels and increased heat consumption. When the anterior hypothalamus cools, reactions develop aimed at increased heat production and heat retention: trembling, piloerection (raising of hair), constriction of peripheral vessels. Peripheral heat and cold thermoreceptors carry information about the ambient temperature to the hypothalamus, and before the temperature of the brain changes, the corresponding reflex responses are activated in advance. Behavioral and endocrine responses activated by cold are controlled by the posterior hypothalamus, while those activated by heat are controlled by the anterior hypothalamus. After removal of the brain in front of the hypothalamus, animals remain warm-blooded, but the accuracy of temperature regulation deteriorates. Destruction of the anterior hypothalamus in animals makes it impossible to maintain body temperature.

Tone of the autonomic nervous system. Under natural conditions, the sympathetic and parasympathetic centers of the autonomic nervous system are in a state of continuous excitation, called “tone.” The phenomenon of constant tone of the autonomic nervous system is manifested primarily in the fact that a constant flow of impulses with a certain repetition frequency flows along the efferent fibers to the organs. It is known that the state of the tone of the parasympathetic system best reflects the activity of the heart, especially heart rate, and the state of the tone of the sympathetic system - vascular system, in particular, the value of blood pressure (at rest or when performing functional tests). Many aspects of the nature of tonic activity remain little known. It is believed that the tone of nuclear formations is formed mainly due to the influx of sensory information from reflexogenic zones, separate groups interoreceptors, as well as somatic receptors. At the same time, the existence of its own pacemakers - pacemakers, located mainly in the medulla oblongata, cannot be ruled out. The nature of the tonic activity of the sympathetic, parasympathetic and metasympathetic divisions of the autonomic nervous system may also be associated with the level of endogenous modulators (direct and indirect action), adrenoreactivity, cholinoreactivity and other types of chemoreactivity. The tone of the autonomic nervous system should be considered as one of the manifestations of the homeostatic state and at the same time one of the mechanisms for its stabilization.

Constitutional classification of ANS tone in humans. The predominance of tonic influences of the parasympathetic and sympathetic parts of the autonomic nervous system served as the basis for the creation of a constitutional classification. Back in 1910, Eppinger and Hess created the doctrine of sympathicotonia and vagotonia. They divided all people into two categories - sympathicotonics and vagotonics. They considered signs of vagotonia rare pulse, deep slow breathing, reduced blood pressure, narrowing of the palpebral fissure and pupils, a tendency to hypersalivation and flatulence. Now there are already more than 50 signs of vagotonia and sympathicotonia (only 16% of healthy people can identify sympathicotonia or vagotonia). Recently A.M. Greenberg proposes to distinguish seven types of autonomic reactivity: general sympathicotonia; partial sympathicotonia; general vagotonia; partial vagotonia; mixed reaction; general intense reaction; general weak reaction.

The question of the tone of the autonomic (autonomic) nervous system requires additional research, especially considering the great interest shown in medicine, physiology, psychology and pedagogy. It is believed that the tone of the autonomic nervous system reflects the process of biological and social adaptation of a person to various environmental conditions and lifestyle. Assessing the tone of the autonomic nervous system is one of the difficult tasks of physiology and medicine. There are special methods for studying autonomic tone. For example, studying cutaneous autonomic reflexes, in particular the pilomotor reflex, or the “ goose bumps“(it is caused by painful or cold irritation of the skin in the area of ​​the trapezius muscle), with a normotonic type of reaction in healthy people, the formation of “goose bumps” occurs. When the lateral horns, anterior roots of the spinal cord and the borderline sympathetic trunk are affected, this reflex is absent. When studying the sweat reflex, or aspirin test (ingestion of 1 g of aspirin dissolved in a glass of hot tea), diffuse sweating appears in a healthy person (positive aspirin test). If the hypothalamus or the pathways connecting the hypothalamus with the sympathetic neurons of the spinal cord are damaged, diffuse sweating is absent (negative aspirin test).

When assessing vascular reflexes, local dermographism is often examined, i.e. vascular response to stroke irritation of the skin of the forearm or other parts of the body with the handle of a neurological hammer. With mild skin irritation, a white stripe appears after a few seconds in normotensive patients, which is explained by spasm of the superficial skin vessels. If the irritation is applied more strongly and slowly, then in normotensive patients a red stripe appears, surrounded by a narrow white border - this is local red dermographism, which occurs in response to a decrease in sympathetic vasoconstrictor effects on the vessels of the skin. With increased tone of the sympathetic department, both types of irritation cause only a white stripe (local white dermographism), and with increased tone of the parasympathetic system, i.e. with vagotonia, in humans, both types of irritation (both weak and strong) cause red dermographism.

Orthostatic reflex Prevel consists of actively transferring the subject from a horizontal to a vertical position, counting the pulse before the test begins and 10 - 25 s after its completion. With a normotonic type of reaction, the heart rate increases by 6 beats per minute. A higher pulse rate indicates a sympathetic-tonic type of reaction, while a slight increase in pulse (no more than 6 beats per minute) or a constant pulse indicates increased tone parasympathetic department.

When studying painful dermographism, i.e. When the skin is irritated with a sharp pin, a red stripe 1 - 2 cm wide appears on the skin of normotensive patients, surrounded by narrow white lines. This reflex is caused by a decrease in tonic sympathetic influences on the vessels of the skin. However, it does not occur when the vasodilator fibers going to the vessel as part of the peripheral nerve are damaged, or when the depressor part of the bulbar vasomotor center is damaged.

The segmental apparatus of the brain stem is a set of anatomically and functionally interconnected structures designed to carry out unconditioned (innate) reflexes that close at the level of the brain stem. Examples of such reflexes are sucking, swallowing, corneal, cough, etc.

Part segmental apparatus The brain stem includes the following structures.

• 1. Root fibers of the cranial nerves, including the sensory component - V pair (trigeminal nerve), VII pair (facial nerve), IX pair (glossopharyngeal nerve), X pair (vagus nerve). They represent the central processes of the pseudounipolar cells of the trigeminal ganglion (V pairs), geniculate ganglion (VII pairs), superior and inferior ganglia (IX and X pairs), located in the substance of the brain stem. The root fibers end with synaptic endings on interneurons of the brain stem.
• 2. Interneurons, the role of which is played by scattered cells of the reticular formation of the brain stem. The axons of these cells synapse on the neurons of the motor nuclei of the cranial nerves.
• 3. Multipolar neurons of the motor nuclei of the cranial nerves – III pair (oculomotor nerve), IV pair ( trochlear nerve), V pair (trigeminal nerve), VI pair (abducens nerve), VII pair (facial nerve), IX pair (glossopharyngeal nerve), X pair (vagus nerve), XI pair ( accessory nerve) and XII pair (hypoglossal nerve).
• 4. Part of the axons of neurons of the motor nuclei of the cranial nerves, constituting the motor root fibers within the substance of the brain.

The remaining elements of the reflex arcs of unconditioned reflexes belong to the peripheral nervous system (radicular fibers lying outside the brain stem, cranial sensory ganglia, cranial nerves and their branches).

In most cases, interneurons of the segmental apparatus of the brain stem provide transmission nerve impulses on neurons of the motor nuclei of several cranial nerves, not only on their own, but also on the opposite side. For example, when the facial skin in the cheek or lip area is irritated, a newborn develops sucking movements. Receptors, which are the endings of pseudounipolar cells of the node, perceive irritation trigeminal nerve. The propagation of the nerve impulse in the brain stem occurs on the neurons of the motor nuclei of the V, VII, IX, X, XI and XII pairs of cranial nerves. In this regard, chewing, facial muscles, muscles of the palate, pharynx, neck and tongue take part in the sucking act. In this case, the muscles are included in the implementation of the response equally both on their own and on opposite side bodies.

The concept of the reticular formation

The reticular formation is a complex of anatomically and functionally interconnected neurons of the cervical spinal cord and brain stem, surrounded by many fibers running in different directions. Neurons of the reticular formation have long, low-branching dendrites and an axon that gives off a significant number of secondary branches. This allows the neuron to establish contacts with approximately 25 thousand other neurons. Under a microscope, the branches of neurons form a kind of network - the reticulum. It was the network-like arrangement of fibers connecting nerve cells with each other that served as the basis for the proposed name.

The structural elements of the reticular formation in the cervical and upper thoracic segments of the spinal cord are localized between the posterior and lateral horns, in the rhomboid and midbrain - in the tegmentum, in the diencephalon - as part of the thalamus.

Along with numerous individual neurons, varying in shape and size, the brain stem contains nuclei of the reticular formation. Scattered neurons of the reticular formation primarily play important role in providing segmental reflexes that close at the level of the brain stem. They act as interneurons during the implementation of such reflex acts as swallowing, corneal reflex, etc.

The significance of many nuclei of the reticular formation has also been clarified. Thus, the nuclei located in the medulla oblongata have connections with the vegetative nuclei of the vagus and glossopharyngeal nerves, sympathetic nuclei of the spinal cord. Therefore, they participate in the regulation of cardiac activity, respiration, vascular tone, gland secretion, etc.

The nuclei of Cajal and Darkshevich, belonging to the reticular formation of the midbrain, through the medial longitudinal fasciculus have connections with the nuclei of the III, IV, VI, VIII and XI pairs of cranial nerves. They coordinate the work of these nerve centers, which is very important for ensuring combined rotation of the head and eyes. The reticular formation of the brain stem has great importance in maintaining the tone of skeletal muscles by sending tonic impulses to the gamma motor neurons of the motor nuclei of the cranial nerves and the motor nuclei of the anterior horns of the spinal cord.

In the process of evolution, such independent formations as the red nucleus and substantia nigra emerged from the reticular formation. In addition, a number of nuclei of the reticular formation of the brain stem in the process of evolution acquired the role of vital centers: the respiratory and vasomotor centers of the medulla oblongata; centers of thermoregulation, hunger and satiety, vegetative functions, etc. located in the diencephalon.

The scattered cells and nuclei of the reticular formation are approached by collaterals from the spinal, medial, trigeminal and lateral lemniscus or directly from the sensory nuclei of the cranial nerves. From the neurons of the reticular formation, efferent fibers are directed to the motor nuclei of the cranial nerves, to the cerebellum, to the motor nuclei of the anterior horns of the spinal cord.

The main descending tract is the reticular-spinal tract, which originates in the brain stem and goes to the neurons of the anterior horns of the spinal cord, giving collaterals to the motor nuclei of the cranial nerves. This pathway conducts tonic impulses to these formations.

From neurons of the medial and reticular nuclei of the visual thalamus to various areas In the cortex of the cerebral hemispheres there are thalamo-cortical fibers. A feature of these pathways is the diffuse nature of their distribution - they end not only in all areas, but also in all layers of the cerebral cortex. In this regard, nonspecific afferent impulses from the reticular formation of the spinal cord and brain stem enter the cortex. Nonspecific afferent impulses activate the cerebral cortex, necessary for the perception of specific stimuli. The latter enter the projection centers of the cortex along specialized afferent pathways from the communication nuclei of the thalamus and geniculate bodies. It should be emphasized the important role of nonspecific afferent reticular fibers in the selection of information (differentiated conduction of impulses) entering the cerebral cortex. Interruption of the flow of nonspecific afferent impulses leads to a decrease in cortical tone, apathy and the onset of sleep.

It should be noted that the cerebral cortex, in turn, sends impulses along the cortico-reticular pathways to the reticular formation. These impulses arise mainly in the cortex of the frontal lobe and pass through pyramid paths. Cortico-reticular connections have either an inhibitory or excitatory effect on the reticular formation of the brain stem and correct the passage of impulses along the efferent pathways (selection of efferent information).

Thus, there is a two-way connection between the reticular formation and the cerebral cortex, which ensures self-regulation in the activity of the nervous system. Muscle tone, the functioning of internal organs, mood, concentration, memory, etc. depend on the functional state of the reticular formation.

In general, the reticular formation creates and maintains the conditions for complex reflex activity with the participation of the cerebral cortex, performing the following main functions:

• 1) providing segmental reflexes - scattered cells act as interneurons (swallowing, sneezing, corneal reflex, pupillary reflex etc.);
• 2) maintaining the tone of skeletal muscles - cells of the reticular formation send tonic impulses to the motor nuclei of the cranial and spinal nerves, mainly along the reticular-spinal tract;
• 3) correction of the conduction of nerve impulses - thanks to the reticular formation, impulses can either be significantly enhanced or significantly weakened depending on the state of the nervous system;
• 4) active influence on higher centers the cerebral cortex, which leads either to a decrease in cortical tone, apathy and the onset of sleep, or to an increase in performance, euphoria, participating in the regulation of sleep and wakefulness, etc.;
• 5) participation in the regulation of cardiac activity, respiration, vascular tone, gland secretion and other autonomic functions (brain stem centers).

Autonomic nervous system in operation human body plays no less important role than the central one. Its various departments control the acceleration of metabolism, the renewal of energy reserves, the control of blood circulation, respiration, digestion and more. Knowledge about what the human autonomic nervous system is for, what it consists of, and how it works is important for a personal trainer. a necessary condition his professional development.

The autonomic nervous system (also known as autonomic, visceral and ganglionic) is part of the entire nervous system of the human body and is a kind of aggregator of central and peripheral nerve formations, which are responsible for regulating the functional activity of the body, necessary for the appropriate reaction of its systems to various stimuli. It controls the functioning of internal organs, internal glands and external secretion, as well as blood and lymphatic vessels. Plays an important role in maintaining homeostasis and the adequate course of the body’s adaptation processes.

The work of the autonomic nervous system is in fact not controlled by humans. This suggests that a person is not able to influence the functioning of the heart or digestive tract through any effort. However, it is still possible to achieve conscious influence on many parameters and processes that are controlled by the ANS, in the process of undergoing a complex of physiological, preventive and therapeutic procedures using computer technology.

Structure of the autonomic nervous system

Both in structure and function, the autonomic nervous system is divided into sympathetic, parasympathetic and metasympathetic. The sympathetic and parasympathetic center controls the cortex cerebral hemispheres and hypothalamic centers. Both the first and second sections have a central and peripheral part. The central part is formed from the cell bodies of neurons that are found in the brain and spinal cord. Such formations of nerve cells are called vegetative nuclei. Fibers that arise from the nuclei, autonomic ganglia that lie outside the central nervous system, and nerve plexuses within the walls of the internal organs form the peripheral part of the autonomic nervous system.

• The sympathetic nuclei are located in the spinal cord. The nerve fibers that branch from it end outside the spinal cord in the sympathetic ganglia, and from them the nerve fibers that go to the organs originate.
• Parasympathetic nuclei are located in the midbrain and medulla oblongata, as well as in the sacral part of the spinal cord. Nerve fibers of the nuclei of the medulla oblongata are present in the vagus nerves. The nuclei of the sacral part conduct nerve fibers to the intestines and excretory organs.

The metasympathetic nervous system consists of nerve plexuses and small ganglia within the walls of the digestive tract, as well as the bladder, heart and other organs.

Structure of the autonomic nervous system: 1- Brain; 2- Nerve fibers to the meninges; 3- Pituitary gland; 4- Cerebellum; 5- Medulla; 6, 7- Parasympathetic fibers of the eyes, motor and facial nerves; 8- Star knot; 9- Border pillar; 10- Spinal nerves; 11- Eyes; 12- Salivary glands; 13- Blood vessels; 14- Thyroid gland; 15- Heart; 16- Lungs; 17- Stomach; 18- Liver; 19- Pancreas; 20- Adrenal glands; 21- Small intestine; 22- Large intestine; 23- Kidneys; 24- Bladder; 25- Genital organs.

I- Cervical region; II- Thoracic department; III- Lumbar; IV- Sacrum; V- Coccyx; VI- Vagus nerve; VII- Solar plexus; VIII- Superior mesenteric node; IX- Inferior mesenteric node; X- Parasympathetic nodes of the hypogastric plexus.

The sympathetic nervous system speeds up metabolism, increases stimulation of many tissues, and activates the body's strength for physical activity. The parasympathetic nervous system helps regenerate wasted energy reserves and also controls the functioning of the body during sleep. The autonomic nervous system controls the organs of circulation, respiration, digestion, excretion, reproduction, and among other things, metabolism and growth processes. By and large, the efferent section of the ANS controls the nervous regulation of the work of all organs and tissues with the exception of skeletal muscles, which are controlled by the somatic nervous system.

Morphology of the autonomic nervous system

The release of the ANS is associated with characteristic features its structures. These features usually include: localization of the vegetative nuclei in the central nervous system; accumulation of bodies of effector neurons in the form of nodes in the composition autonomic plexuses; two-neuronality of the neural pathway from vegetative nucleus in the central nervous system to the target organ.

Structure of the spinal cord: 1- Spine; 2- Spinal cord; 3- Articular process; 4- Transverse process; 5- Spinous process; 6- Place of attachment of the rib; 7- Vertebral body; 8- Intervertebral disc; 9- Spinal nerve; 10- Central canal of the spinal cord; 11- Vertebral ganglion; 12- Soft shell; 13- Arachnoid membrane; 14- Hard shell.

The fibers of the autonomic nervous system do not branch in segments, as, for example, in the somatic nervous system, but from three localized areas of the spinal cord remote from each other - the cranial sternolumbar and sacral. As for the previously mentioned sections of the autonomic nervous system, in its sympathetic part the processes of spinal neurons are short, and the ganglion ones are long. In the parasympathetic system the opposite is true. The processes of spinal neurons are longer, and those of ganglion neurons are shorter. It is worth noting here that sympathetic fibers innervate all organs without exception, while the local innervation of parasympathetic fibers is largely limited.

Divisions of the autonomic nervous system

Based on topographical characteristics, the ANS is divided into central and peripheral sections.

• Central department. It is represented by the parasympathetic nuclei of the 3rd, 7th, 9th and 10th pairs of cranial nerves running in the brain stem (craniobulbar region) and nuclei located in the gray matter of the three sacral segments (sacral region). The sympathetic nuclei are located in the lateral horns of the thoracolumbar spinal cord.
• Peripheral department. Represented by autonomic nerves, branches and nerve fibers emerging from the brain and spinal cord. This also includes the autonomic plexuses, nodes of the autonomic plexuses, the sympathetic trunk (right and left) with its nodes, internodal and connecting branches and sympathetic nerves. As well as the terminal nodes of the parasympathetic part of the autonomic nervous system.

Functions of the autonomic nervous system

The main function of the autonomic nervous system is to provide adequate adaptive reaction body to various stimuli. The ANS ensures control of the constancy of the internal environment, and also takes part in multiple responses that occur under the control of the brain, and these reactions can be both physiological and mental in nature. As for the sympathetic nervous system, it is activated when stress reactions occur. It is characterized by a global effect on the body, with sympathetic fibers innervating most organs. It is also known that parasympathetic stimulation In some organs it leads to an inhibitory reaction, and in other organs, on the contrary, to an exciting one. In the vast majority of cases, the action of the sympathetic and parasympathetic nervous systems is opposite.

The autonomic centers of the sympathetic department are located in the chest and lumbar regions spinal cord, parasympathetic centers - in the brain stem (eyes, glands and organs innervated vagus nerve), as well as in sacral region spinal cord (bladder, lower colon and genitals). Preganglionic fibers of both the first and second sections of the autonomic nervous system run from the centers to the ganglia, where they end on postganglionic neurons.

Preganglionic sympathetic neurons originate in the spinal cord and end either in the paravertebral ganglion chain (in the cervical or abdominal ganglion) or in the so-called terminal ganglia. The transmission of stimulus from preganglionic neurons to postganglionic neurons is cholinergic, that is, mediated by the release of the neurotransmitter acetylcholine. Stimulation by postganglionic sympathetic fibers of all effector organs, with the exception of sweat glands is adrenergic, that is, mediated by the release of norepinephrine.

Now let's look at the effect of the sympathetic and parasympathetic departments on specific internal organs.

• Effect of the sympathetic department: on the pupils - has a dilating effect. On arteries – has a dilating effect. On salivary glands– inhibits salivation. On the heart - increases the frequency and strength of its contractions. It has a relaxing effect on the bladder. On the intestines - inhibits peristalsis and enzyme production. On the bronchi and breathing - expands the lungs, improves their ventilation.
• Effect of the parasympathetic department: on the pupils - has a constricting effect. On the arteries - in most organs it has no effect, it causes dilation of the arteries of the genitals and brain, as well as a narrowing of the coronary arteries and arteries of the lungs. On the salivary glands – stimulates salivation. On the heart - reduces the strength and frequency of its contractions. On the bladder – promotes its contraction. On the intestines - enhances peristalsis and stimulates the production of digestive enzymes. On the bronchi and breathing - narrows the bronchi, reduces ventilation of the lungs.

Basic reflexes often occur within a specific organ (for example, in the stomach), but more complex (complex) reflexes pass through the controlling autonomic centers in the central nervous system, mainly in the spinal cord. These centers are controlled by the hypothalamus, whose activity is associated with the autonomic nervous system. The cerebral cortex is the most highly organized nerve center that connects the ANS with other systems.

Conclusion

The autonomic nervous system, through its subordinate structures, activates whole line simple and complex reflexes. Some fibers (afferents) carry stimuli from the skin and pain receptors in organs such as the lungs, gastrointestinal tract, gallbladder, vascular system and genitals. Other fibers (efferent) conduct a reflex response to afferent signals, implementing smooth muscle contractions in organs such as the eyes, lungs, digestive tract, gall bladder, heart and glands. Knowledge about the autonomic nervous system, as one of the elements of the integral nervous system of the human body, is an integral part of the theoretical minimum that a personal trainer should have.