What is the vegetative system responsible for? The autonomic (autonomic) nervous system. Functions of the autonomic nervous system

The autonomic nervous system is an integral part of the peripheral nervous structure that regulates the work internal organs and systems. Her work is carried out reflexively and involuntarily and is not controlled by a person. People do not consciously control the size of blood vessels, pulse rate or pressure. One of the main functions of the ANS is to ensure the physiological state of organs and the body as a whole (homeostasis).

Definition and meaning of the system

The ANS, consisting of numerical neurons, is responsible for the transmission of impulses from the brain to organs and glands. It is believed that it is responsible for the frequency of heart rate, intestinal peristalsis of the human body. The ANS is able to maintain stability against the background of the influence of external or internal factors. Autonomic functions coordinate many processes, including:

  • secretion of hormones;
  • blood flow;
  • breath;
  • digestion;
  • reproduction and excretion processes.

The ANS is divided into 2 subsystems: the sympathetic and parasympathetic divisions (SNS, PNS). Sympathy, features of the structure and work:

  • The SNS is responsible for the body's response: "fight or flight";
  • chemical synapses in the ganglion zone allow sympathetic neurons to communicate with peripheral ones;
  • to designate sympathetic elements, the terms "presynaptic", "postsynaptic" are used: this is how sympathetic and peripheral elements are distinguished;
  • presympathetic elements secrete acetylcholine;
  • the influence of adrenaline and norepinephrine on adrenoreceptors provides a characteristic "fight or flight" reaction.

The structure of the vegetative nervous system unique. Activation of adrenoreceptors in the body leads to a cascade of changes that manifest themselves in different clinics. The functionality of the sympathetic nervous system includes:

  • increased sweating;
  • increased pulse rate (at the same time, conductivity increases significantly and the refractory period decreases);
  • pupil dilation;
  • arterial hypertension.

This department, which regulates the work of many organs, performs protective function for the body from attack. Shows a general catabolic effect. Able to activate the brain, muscles, thyroid, pancreas and adrenal glands. Responsible for enhancing the production of insulin, cortisol and thyroid hormones. It provokes feelings of fear, guilt, sadness, anger and aggressiveness. The system is activated under the influence of anger, stress, physical or psychological overwork.

Features of the parasympathetic system

Parasympathetic - the "rest and assimilation" system. This is a completely opposite system to the SNS. Its activity is aimed at normalizing the function of the body, which was activated under the influence of sympathy. SNS and PNS are two parts of one whole, only their well-coordinated work allows the body to function fully.

System characteristic:

  • the main mediator in the regulation is acetylcholine;
  • stimulation causes the release of acetylcholine in the ganglion;
  • vegetative department with the help of choline stimulates muscarinic receptors of target organs.

The result of the activation of this department of the National Assembly are:

  • reduced sweating;
  • increased peristalsis;
  • decrease in cardiac conduction, decrease in heart rate;
  • pupil constriction;
  • pressure drop.

Among the effects related to the system are:

  • treatment, regeneration and nutrition;
  • anabolic effect;
  • activation of the liver, kidneys, pancreas, spleen, stomach, intestines;
  • increases the production of parathyroid hormone, gland enzymes, bile;
  • includes activation of digestion, immunity and excretion;
  • causes calmness, satisfaction and relaxation;
  • the system is activated by rest, sleep, meditation, relaxation, feelings of sympathy and love.

The metasympathetic department consists of independent formations capable of working up to complete decentralization.

Conductors and conductivity of SNS

VNS allocates special chemical conductors. The main ones are norepinephrine and acetylcholine. ACh is a neurotransmitter. By releasing it, the nervous system responds and controls the work of all sympathetic, postsynaptic and parasympathetic neurons.

SNS uses HA (Specific Chemical Intermediary). NA and AH are considered the main "weapons" of control of the autonomous NS. In addition to neurotransmitters, vasoactive components are released in neurons. Sympathy works through the release of catecholamines. There are several types of such receptors:

  1. Alpha-1 receptors are responsible for muscle contraction. This applies to arteries, veins, structures of the gastrointestinal tract and the pupil. They are located postsynaptically.
  2. Alpha-2 receptors are designed to bind epinephrine and norepinephrine. By this they minimize the influence of alpha-1 receptors. At the same time, they are able to constrict blood vessels (in particular, coronary), contract smooth muscles, and inhibit the release of insulin from the pancreas.
  3. Autonomic beta-1 receptors affect the heart by increasing cardiac output. This causes tachycardia. At the same time, work is stimulated salivary glands.
  4. Beta-2 structures affect muscles and blood vessels. Stimulation of such receptors is carried out by the circulation of catecholamines.

Conductivity of the PNS

The mediator of the system (acetylcholine) affects cholinergic receptors. Some of them are located in the heart. Stimulation of them leads to a slowdown in the work of the heart. Other elements of the human nervous system are found throughout the body. Their activation enhances the synthesis of nitric oxide. This causes smooth muscle relaxation.

To understand the operation of the system, there is a simplified diagram of it. Nerves release neurotransmitters that transmit nerve signals through the gaps (synapses) created. Each organ has special targets that are sensitive to such influence of the neurotransmitter. This allows the structures of each department of the nervous system to exert its influence on a particular organ.

Regulation in the autonomic nervous system is carried out by the human subconscious. Its control is carried out with the help of several centers:

  • the cerebral cortex controls the activity of the hypothalamus;
  • The hypothalamus controls the functions and activity of the elements of the autonomic nervous system. In addition, he is responsible for digestion, heart rate, sweating;
  • the stem brain regulates breathing, heart rate and pressure;
  • spinal cord - on both sides of it is the sympathetic division of the autonomic nervous system.

ANS receptors

Each afferent neuron, its dendrites and axon have receptor properties that make them highly specialized. They only respond to specific species irritants. All of them are realized subconsciously, so a person does not feel these impulses. The exception is pain. These sensory receptors include:

  • photoreceptors that respond to light;
  • thermoreceptors sensitive to temperature changes;
  • mechanoreceptors that respond to stretch or pressure;
  • chemoreceptors that respond to vibrations in the internal chemical composition organism (usually they are sensitive to CO2 and O2).

Autonomous or visceral motor neurons belong to the ganglia of the sympathetic and parasympathetic systems. The visceral elements of the SNS are able to indirectly innervate the smooth muscles of the arteries and the heart. Autonomic motor neurons are called autonomous (because of their ability to function if their nerve supply is significantly damaged). They can respond to the slightest stimulation.

The sympathetic nervous system, like all autonomics, controls many body functions:

  • lungs - relaxation of smooth muscles;
  • Gastrointestinal tract - influence on peristalsis, saliva production, sphincter control and insulin secretion;
  • immunity;
  • fluid balance - narrows the arteries of the kidneys, reduce the synthesis of renin;
  • reproduction;
  • urinary system under the influence nervous regulation relaxes.

The ANS controls energy expenditure (the sympathetic is the mediator of such expenditures, the parasympathetic plays a general strengthening role). Health can seriously deteriorate if the relationship between these subtypes of the ANS is disrupted. Pathology may develop (due to a violation of stability in the body).

Normally, the departments of the system are designed to oppose each other. When one of them is activated, the other begins to work to return the first to its original position. Therefore, the constant action of only one part of the nervous system leads to a significant drop in tone in the other. This leads to deterioration in health.

Joint work of both systems

Well-coordinated work is clearly visible in the reproductive and urinary systems:

  1. Reproduction. Sympathetic has a stimulating effect on the production of germ cells and their secretion. Parasympathetic dilates blood vessels. Due to this, an erection of the penis and clitoris occurs.
  2. Urination. Parasympathetic contraction of the bladder.

Similar structures have only sympathetic fibers. The regulation of their work is to control the tone of the sympathetic elements. By strengthening or weakening the tone of the system, it is possible to achieve control over the work of such organs.

Threatening situations lead to the activation of the “emotional” brain. The anterior part of the hypothalamus excites the sympathetic. With help vagus nerve, medulla oblongata there is a change in the activity of digestion, pulmonary, cardiac and urinary systems.

Severe stress can paralyze the sympathetic system. At the same time, its activities are completely stopped. The person freezes in place because he is unable to move. Often there is a loss of control over urination and defecation. This is a short-term condition, but it is possible in any stressful situations.

Neurologists identify several diseases that are the result of a malfunction of the ANS. At orthostatic hypotension The patient complains of dizziness, fainting, poor eyesight. Horner's syndrome is characterized by low sweating and droopy eyelids. Such a clinic is associated with damage to the sympathetic nerves passing to the face.

Hirschsprung Syndrome - congenital pathology associated with intestinal expansion and severe constipation. Such a clinic is due to the absence of specific ganglia. Vasovagal syncope can lead to fainting. This phenomenon is associated with an abnormal ANS response to a trigger.

Raynaud's syndrome is a disorder in which the color of the fingers and toes is disturbed. This phenomenon is associated with hyperactivation of the SNS, which is caused by stress and cold. Spinal shock refers to severe trauma or damage to the spinal cord. At the same time, the patient complains of sweating, severe hypertension, loss of bowel control. With the manifestation of symptoms indicating disorders in the autonomic nervous system, it is required urgent help neurologist.

autonomic nervous system- an important part of the whole system 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 the direct participation of a 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 people know 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 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 divisions function well, then this helps to avoid Negative consequences 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 parasympathetic.


Nervous when playing sports autonomic system help maintain a healthy balance blood pressure and good 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 nerve is located only in spinal cord as opposed to 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. This ensures a constant workflow of internal organs, and supports all the necessary vital functions sympathetic nervous division.

In the cervical region under control is carotid artery, in the chest - lungs and heart. 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 and adjust to different environment a habitat.

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. Security normal operation 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. Responsible for the expansion of the bronchi and a decrease in appetite thoracic region. Adrenaline is produced by the sympathetic nerve section in the lumbar region. Relaxation Bladder- in the sacral area.

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?


The sympathetic and parasympathetic divisions may work together, but provide different influence on the body.

  1. Sympathetic fibers are small and short. Parasympathetic have an elongated shape.
  2. Sympathy is enveloped in branches gray color. 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 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, 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 is, as it were, “scattered” throughout the brain. It 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 department. 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 requires outside help. 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 department will provide normal life organism. Dysfunction of at least one of the departments can lead to serious illnesses not only the nervous system, but also the respiratory, motor and cardiovascular systems. The poor performance of the parasympathetic and sympathetic department is due to 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 human nervous system consists of neurons that perform its main functions, as well as auxiliary cells that ensure their vital activity or performance. All nerve cells are folded into special tissues located in the skull, human spine in the form of organs of the brain or spinal cord, as well as throughout the body in the form of nerves - fibers from neurons that grow from one another, intertwining many times, forming a single neural network that penetrates in every even the smallest corner of the body.

According to the structure and functions performed, it is customary to divide the entire nervous system into central (CNS) and peripheral (PNS). The central one is represented by command and analyzing centers, and the peripheral one is represented by an extensive network of neurons and their processes throughout the body.

The functions of the PNS are mostly executive, since its task is to convey information to the central nervous system from organs or receptors, to transmit orders from the central nervous system to organs, muscles and glands, and also to control the execution of these orders.

The peripheral system, in turn, consists of two subsystems: somatic and vegetative. The functions of the somatic subdivision are represented by motor activity of skeletal and motor muscles, as well as sensory (collection and delivery of information from receptors). Another somatic maintains a constant muscle tone of the skeletal muscles. The vegetative system, on the other hand, has more complex, rather managerial functions.

The functions of the ANS, in contrast, do not consist in simply receiving or transmitting information from an organ to the brain and vice versa, but in controlling the unconscious work of internal organs.

Regulates the activity of all internal organs, as well as from large to the smallest glands, regulates the functioning of the muscles of hollow organs (heart, lungs, intestines, bladder, esophagus, stomach, etc.), and also by controlling the work of internal organs can regulate the entire metabolism and homeostasis of a person as a whole.

It can be said that the ANS regulates the activity of the organism, which it carries out unconsciously, not obeying the mind.

Structure

The structure is not too different from the sympathetic, since it is represented by the same nerves, ultimately leading to the spinal cord or directly to the brain.

According to the functions performed by the neurons of the vegetative part of the peripheral system, it is conditionally divided into three subdivisions:

  • The sympathetic division of the ANS is represented by nerves from neurons that excite the activity of an organ or transmit an excitatory signal from special centers located in the central nervous system.
  • The parasympathetic department is arranged in exactly the same way, only instead of excitatory signals it brings inhibitory signals to the organ, which reduces the intensity of its activity.
  • The metasympathetic subdivision of the vegetative division, which regulates the contraction of hollow organs, is its main difference from the somatic one and causes it to be somewhat independent from the central nervous system. It is built in the form of special microganglionic formations - sets of neurons located directly in the controlled organs, in the form of intramural ganglia - nerve nodes that control the contractility of the organ, as well as nerves connecting them to each other and to the rest of the human nervous system.

The activity of the metasymptomatic subdivision can be either independent or corrected by the somatic nervous system with the help of reflex action or hormonal, and also partially by the central nervous system, which controls endocrine system responsible for the production of hormones.

The neural fibers of the ANS intertwine and connect with the somatic nerves, and then transmit information to the central through the main large nerves: spinal or cranial.

There is none major nerve, which would perform only vegetative or somatic functions, this division occurs already at a smaller or, in general, cellular level.

Diseases to which she is subject

Although people divide the human nervous system into subdivisions, in fact it is a special network, each part of which is closely connected with the others and depends on them, and not only exchanges information. Diseases of the autonomic part of the whole nervous system are diseases of the PNS as a whole and are represented by either neuritis or neuralgia.

  • Neuralgia - inflammatory process in the nerve, which does not lead to its destruction, but without treatment can go into neuritis.
  • Neuritis is an inflammation of a nerve or its injury, accompanied by the death of its cells or a violation of the integrity of the fiber.

Neuritis, in turn, is of the following types:

  • Multineuritis, when a lot of nerves are affected at once.
  • Polyneuritis, the cause of which is the pathology of several nerves.
  • Mononeuritis - neuritis of only one nerve.

These diseases are caused by negative impact directly on the nerve tissue caused by the following factors:

  • Pinching or compression of the nerve by muscles, tissue tumors, neoplasms, overgrown ligaments or bones, aneurysms, etc.
  • Hypothermia of the nerve.
  • Injury to the nerve or nearby tissues.
  • Infections.
  • Diabetes.
  • Toxic damage.
  • Degenerative processes, for example, multiple sclerosis.
  • Lack of circulation.
  • Lack of any substances, such as vitamins.
  • Metabolism disorder.
  • Irradiation.

In this case, polyneuritis or multineuritis usually cause the last eight causes.

In addition to neuritis and neuralgia, in the case of the ANS, there may be a pathological imbalance in the work of its sympathetic department with the parasympathetic one due to hereditary abnormalities, negative brain damage or due to immaturity of the brain, which is quite common in childhood, when the sympathetic and parasympathetic centers begin to take over in turn, developing unevenly, which is the norm and goes away by itself with age.

Center failures are extremely rare.

Consequences of disruption

The consequences of violations of the work of the VNS are improper execution its functions to regulate the activity of internal organs, and as a result - to the failure of their work, which at least can be expressed in improper excretory activity of the secretory glands, for example, hypersalivation (salivation), sweating or, conversely, lack of sweat, covering the skin with fat or lack of it workings sebaceous glands. The consequences of disruption of the work of the ANS lead to failures in the activity of vital organs: the heart and respiratory organs, but it rarely comes to this. Severe polyneuritis usually causes small complex deviations in the functioning of internal organs, resulting in a violation of metabolism and physiological homeostasis.

It is the coordinated work of the sympathetic and parasympathetic divisions of the ANS that carries out the main work on regulation. The fragile balance is disturbed quite often different reasons and leads to wear or, conversely, to the oppression of any organ or their combination. In the case of glands that produce hormones, this can lead to not very unpleasant consequences.

Restoration of ANS functions

The neurons that make up the ANS in the same way do not know how to divide and regenerate the tissues that make up, like the cells of other parts of the human nervous system. The treatment of neuralgia and neuritis is standard, it does not differ in case of damage to the autonomic nerve fibers from damage to the somatic nerves of the human PNS.

Restoration of functions occurs according to the same principle as in any nervous tissue by redistributing responsibilities between neurons, as well as building up new processes with the remaining cells. Sometimes irretrievable loss of any functions or their failure is possible, usually this does not lead to vital pathologies, but sometimes it requires immediate intervention. Such an intervention includes stitching the damaged nerve or installing a pacemaker that regulates its contractions instead of the metasympathetic subdivision of the ANS.

Autonomous, it is also the autonomic nervous system, ANS, is a part of the human nervous system that regulates internal processes, controls almost all internal organs, and is also responsible for adapting a person to new living conditions.

The main functions of the autonomic nervous system

Trophotropic - maintaining homeostasis (constancy internal environment organism, regardless of changes in external conditions). This feature helps to save normal functioning body in almost any environment.

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

Ergotropic - ensuring normal physical and mental species activity of the organism depending on the specific conditions of human existence at a particular point in time.

In simple words, this function enables the autonomic nervous system to mobilize the body's energy resources to save human life and health, which is necessary, for example, in an emergency situation.

At the same time, the functions of the autonomic nervous system also extend to the accumulation and “redistribution” of energy depending on the activity of a person at a particular point in time, that is, it ensures the normal rest of the body and the 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. The suprasegmental division of the human autonomic nervous system includes the following functional units:

  1. reticular formation of the brain. It contains the respiratory and control centers of cardio-vascular system responsible for sleep and wakefulness. It is a kind of "sieve" that controls the impulses entering the brain, primarily during sleep.
  2. Hypothalamus. Regulates the relationship between somatic and vegetative activity. It contains the most important centers that maintain constant and normal for the body indicators of body temperature, heart rate, blood pressure, hormonal background, as well as controlling sensations of satiety and hunger.
  3. limbic system. This center controls the appearance and extinction of emotions, regulates the daily routine - sleep and wakefulness, is responsible for maintaining 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 it is quite possible to cope with the violation of autonomic regulation by controlling emotions:

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

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

Apparently, positive attitude and self-hypnosis help vegetative centers cope with their own pathologies on their own and save a person from unpleasant manifestations of vegetative-vascular dystonia.

Segmental division of the VNS

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

Each of them has a central and peripheral parts. 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, vegetative 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. terminal nodes of the parasympathetic division of the autonomic nervous system.

In addition, some individual organs are "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 from the corresponding side. The exception is the regulation of the activity of the heart, stomach and liver: they are controlled by two trunks at the same time.

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

The parasympathetic autonomic nervous system acts in the opposite way 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 a dream, and it is due to its work that the body manages to relax and accumulate 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. The sympathetic NS is responsible for stimulation. Its main functions are as follows:

  1. narrowing or toning blood vessels, acceleration of blood flow, increased blood pressure, body temperature;
  2. increased heart rate, organization of additional nutrition of certain organs;
  3. slowing down digestion, reducing intestinal motility, reducing the production of digestive juices;
  4. reduces sphincters, reduces the secretion of glands;
  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 energy storage and nutrients. It affects organs and systems as follows:

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

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

The structure of the autonomic nervous system that controls our organs, regardless of consciousness, its function. Participation in the adaptive reactions of the body. The mechanism of transmission of a nerve impulse (the structure of the synapse). Acetylcholine and norepinephrine are the main mediators of this system and their effects.

Why can't we stop our own heart at will or stop the process of digesting food in the stomach, why does a sudden fright make the heart beat faster? There is a separate part of the human nervous system that controls many of the involuntary functions of our body. It is called autonomic nervous system . This is an autonomic nervous system, the activity of which is not controlled by our consciousness. Under the control of this system is the activity of various glands, the contraction of smooth muscles, the work of the kidneys, the contraction of the heart and many other functions.

The autonomic nervous system maintains blood pressure, sweating, body temperature, metabolic processes, the activity of internal organs, blood and lymphatic vessels at a level set by nature. Together with endocrine system , which we will talk about in the next chapter, it regulates the constancy of the composition of blood, lymph, tissue fluid ( internal environment ) in the body, controls metabolism and interacts individual bodies in organ systems (respiration, circulation, digestion, excretion and reproduction).

The structure of the autonomic nervous system.

Their functions, as a rule, are opposite (Figure 1.5.17). As can be seen from Figure 1.5.17, if the nerves of the sympathetic department stimulate some kind of reaction, then the nerves of the parasympathetic suppress it. These processes of multidirectional influence on each other eventually mutually balance each other, as a result, the function is maintained at the appropriate level. It is precisely on the excitation or inhibition of one of these opposite in their direction of influences that the action of drugs is often directed.

Excitation of sympathetic nerves causes vasodilation of the brain, skin, peripheral vessels; pupil dilation; decline excretory function salivary glands and strengthening - sweat; expansion of the bronchi; acceleration and strengthening of heart contractions; contraction of the muscles that raise the hair; weakening of the motility of the stomach and intestines; increased secretion of adrenal hormones; relaxation of the bladder; has a stimulating effect on the genitals, causes uterine contractions. Parasympathetic nerve fibers give “orders” that are reversed in their direction: for example, the vessels and the pupil - to narrow, the muscles of the bladder - to contract, and so on.

The autonomic nervous system is very sensitive to emotional impact. Sadness, anger, anxiety, fear, apathy, sexual arousal - these conditions cause changes in the functions of organs that are under the control of the autonomic nervous system. For example, a sudden fright makes the heart beat faster, breathing becomes more frequent and deep, glucose is released from the liver into the blood, the secretion of digestive juice stops, dry mouth appears. The body prepares for a quick reaction to danger and, if required, for self-defense. So with prolonged and strong emotional stress and excitement, serious illnesses, such as the: hypertension, coronary heart disease, stomach ulcer and many others.

Imagine walking through hilly terrain. While the road passes through its flat part, you walk slowly, your breathing is even, and your heart beats calmly. At the same time, each cell of the body always remembers the genetically programmed optimal mode its functioning and further strives to maintain it as a reference. We have already mentioned in that the property of a living organism to carry out activities aimed at maintaining the constancy of the internal environment is called homeostasis .

Then the road went uphill and as soon as this happened, your body began to do additional work to overcome the force of gravity. To perform this work, all the cells of the body participating in it required additional energy, which comes from an increase in the rate of combustion of energy-intensive substances that the cell receives from the blood.

At the moment when the cell began to burn these substances more than blood brings at a given blood flow rate, it informs the autonomic nervous system about the violation of its constant composition and deviation from the reference energy state. The central divisions of the autonomic nervous system at the same time form control action, leading to a set of changes to restore energy starvation: increased respiration and heart contractions, accelerated breakdown of proteins, fats and carbohydrates, and so on (Figure 1.5.18).

Figure 1.5.18. Functional model for describing the autonomic nervous system

As a result, due to an increase in the amount of oxygen entering the body and the rate of blood flow, the cell participating in the work switches to a new mode, in which it gives off more energy under conditions of increased physical activity, but also consumes more of it exactly as much as necessary to maintain the energy balance that provides the cell with a comfortable state. Thus, we can conclude:

And, although it acts autonomously, that is, turning off consciousness does not lead to the cessation of its work (you continue to breathe, and the heart beats evenly), it reacts to the slightest changes in the work of the central nervous system. It can be called the “wise partner” of the central nervous system. It turns out that mental and emotional activity is also work carried out due to the consumption of additional energy by the cells of the brain and other organs. At the same time, other cells work, but processes similar to those described earlier occur with them.

For those who want to study in more detail the work of the autonomic nervous system, we give its description in more detail.

As we said above, the autonomic nervous system is represented in central departments sympathetic and parasympathetic nuclei located in the brain and spinal cord, and on the periphery - nerve fibers and nodes (ganglia).

The nerve fibers that make up the branches and twigs of this system diverge throughout the body, accompanied by a network of blood vessels. Their total length is about 150,000 km.

In our body, all internal tissues and organs “subordinate” to the autonomic nervous system are equipped with nerves ( innervated ), which, like sensors, collect information about the state of the body and transmit it to the appropriate centers, and from them they convey corrective actions to the periphery.

Just like the central nervous system, the autonomic system has sensitive ( afferent ) endings (inputs) that ensure the occurrence of sensations, and executive (motor, or efferent ) endings that transmit modifying influences from the center to the executive body. Physiologically, this process is expressed in the alternation of the processes of excitation and inhibition, during which the transmission of nerve impulses that occur in the cells of the nervous system ( neurons ).

The transition of a nerve impulse from one neuron to another or from neurons to cells of the executive (effector) organs occurs at the points of contact of cell membranes, called synapses (Figure 1.5.19). The transfer of information is carried out by special chemicals-intermediaries ( mediators ) secreted from nerve endings in synaptic cleft . In the nervous system, these substances are called neurotransmitters .

At rest, these mediators, produced in the nerve endings, are in special vesicles. Let's try to briefly consider the work of these mediators in Figure 1.5.20. Conventionally (since it takes a matter of fractions of a second), the entire process of information transfer can be divided into four stages. As soon as an impulse arrives at the presynaptic ending, inside cell membrane due to the entry of sodium ions, a positive charge is formed, and the vesicles with the mediator begin to approach the presynaptic membrane (stage I in Figure 1.5.20). At the second stage, the transmitter enters the synaptic cleft from the vesicles at the point of their contact with the presynaptic membrane. After release from the nerve endings (stage II), the neurotransmitter penetrates the synaptic cleft by diffusion and binds to its receptors on the postsynaptic cell membrane executive body or other nerve cell(stage III). Activation of receptors triggers biochemical processes in the cell, leading to a change in its functional state in accordance with what signal was received from the afferent links. At the organ level, this is manifested by contraction or relaxation of smooth muscles (constriction or dilation of blood vessels, acceleration or slowdown and strengthening or weakening of heart contractions), secretion, and so on. And, finally, at stage IV, the synapse returns to a resting state either due to the destruction of the mediator by enzymes in the synaptic cleft, or due to its transport back to the presynaptic ending. The signal to stop the release of the mediator is the excitation of the receptors of the presynaptic membrane.

Figure 1.5.20. Synapse function:

I - arrival of a nerve impulse; II - release of the mediator into the synaptic cleft; III - interaction with the receptors of the postsynaptic membrane; IV - the "fate" of the mediator in the synaptic cleft - the return of the synapse to a state of rest

1- recapture of the mediator; 2 - destruction of the mediator by the enzyme; 3- excitation of presynaptic receptors

As we have already said, in the autonomic nervous system, information is transmitted mainly with the help of neurotransmitters - acetylcholine and norepinephrine. Therefore, transmission pathways and synapses are called cholinergic (mediator - acetylcholine) or adrenergic (mediator - norepinephrine). Similarly, the receptors to which acetylcholine binds are called cholinergic receptors and norepinephrine receptors

Adrenoreceptors, based on their different sensitivity to chemical compounds, are divided into alpha and beta adrenoreceptors, which also have several varieties depending on localization.

A network of nerve fibers permeates everything human body thus, cholinergic and adrenergic receptors are located throughout the body. A nerve impulse propagating throughout the entire nervous network or its bundle is perceived as a signal for action by those cells that have the appropriate receptors. And, although cholinergic receptors are localized to a greater extent in the muscles of internal organs ( gastrointestinal tract, genitourinary system, eyes, heart, bronchioles and other organs), and adrenoreceptors - in the heart, blood vessels, bronchi, liver, kidneys and fat cells, they can be found in almost every organ. The impacts in the implementation of which they serve as intermediaries are very diverse.

Drugs that affect different types receptors will be presented in chapter 3.2.

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