Humoral regulation is faster than nervous regulation. Nervous and humoral regulation of activity

Sensory systems

Sensory (sensitive) systems perceive and analyze stimuli entering the brain from the external environment and from various internal organs and tissues of the body. These include motor, visual, vestibular, auditory, tactile, temperature, pain and others.

Sensory systems play a large role in learning and performing motor actions. They perceive individual irritations and ensure the coordination of all systems. When movements are repeated repeatedly, temporary connections are formed between the centers of individual sensory systems, which contribute to the improvement of motor activity.

The motor sensory system is of greatest importance when performing movements. Without her participation, even the simplest motor operation cannot be carried out. Afferent (coming from motor receptors) impulses are indispensable components for ensuring movement control.

The visual sensory system provides the perception of space and changes occurring in the environment. Visual information is necessary to control movement in the vast majority of physical activities.

The vestibular sensory system ensures the preservation of body balance, promotes orientation in space, and improves coordination of movements.

The tactile sensory system is important. Its receptors, acting in concert with the receptors of the motor system, provide information about the amplitude of movements. They become irritated due to changes in skin tension. When performing gymnastic exercises, tactile receptors provide information about the contact of the body with sports equipment, in wrestling - with the body of a partner, etc.

Body temperature is an indicator of the thermal state of the human body, reflecting the relationship between the body’s heat production processes and its heat exchange with the environment.

Pain is a psychophysiological reaction of the body that occurs when sensory nerve endings are severely irritated.

Regulation of the functions of cells, tissues and organs, the relationship between them, i.e. ensuring the integrity of the body and the unity of the body and the external environment is carried out by the nervous system and the humoral pathway.

Nervous regulation is carried out by the brain and spinal cord through the nerves that supply all the organs of our body. The body is constantly exposed to certain irritations. The body responds to all these irritations with a certain activity or, as they say, the body’s function adapts to constantly changing environmental conditions. Thus, a decrease in air temperature is accompanied not only by a narrowing of blood vessels, but also by an increase in metabolism in cells and tissues and, consequently, an increase in heat generation. Thanks to this, a certain balance is established between heat transfer and heat generation, the body does not become hypothermic, and body temperature remains constant. Irritation of the mouth's taste buds by food causes the release of saliva and other digestive juices, under the influence of which food is digested. Thanks to this, the necessary substances enter the cells and tissues, and a certain balance is established between dissimilation and assimilation. This principle is used to regulate other body functions.

Nervous regulation is reflexive in nature. Irritations are perceived by receptors. The resulting excitation from the receptors is transmitted along the afferent (sensory) nerves to the central nervous system, and from there along the efferent (motor) nerves to the organs that carry out certain activities. Such responses of the body to stimuli carried out through the central nervous system are called reflexes. The path along which excitation is transmitted during a reflex is called a reflex arc. Reflexes are varied. I.P. Pavlov divided all reflexes into unconditioned and conditioned. Unconditioned reflexes are innate reflexes that are inherited. An example of such reflexes are vasomotor reflexes (constriction or dilation of blood vessels in response to skin irritation by cold or heat), salivation reflex (secretion of saliva when taste buds are irritated by food) and many others.

Conditioned reflexes are acquired reflexes; they are developed throughout the life of an animal or a person. These reflexes occur only under certain conditions and may disappear. An example of conditioned reflexes is the secretion of saliva when seeing food, when smelling food, even when talking about it.

Humoral regulation (Humor - liquid) is carried out through the blood and other various chemical substances that make up the internal environment of the body. Examples of such substances are hormones secreted by the endocrine glands and vitamins that enter the body with food. Chemicals are carried by the blood throughout the body and affect various functions, in particular the metabolism of cells and tissues. Moreover, each substance affects a specific process occurring in a particular organ. For example, in the pre-launch state, when intense physical activity is expected, the endocrine glands (adrenal glands) release a special hormone, adrenaline, into the blood, which helps to enhance the activity of the cardiovascular system.

The nervous system regulates the body's activities through bioelectric impulses. The main nervous processes are excitation and inhibition that occur in nerve cells. Excitation is an active state of nerve cells when they transmit or direct nerve impulses themselves to other cells: nerve, muscle, glandular and others. Inhibition is a state of nerve cells when their activity is aimed at restoration. Sleep, for example, is a state of the nervous system when the vast majority of nerve cells in the central nervous system are inhibited.

The nervous and humoral mechanisms of regulation of functions are interconnected. Thus, the nervous system has a regulatory effect on organs not only directly through the nerves, but also through the endocrine glands, changing the intensity of the formation of hormones in these organs and their entry into the blood. In turn, many hormones and other substances affect the nervous system. The mutual coordination of the nervous and humoral reactions is ensured by the central nervous system.

In a living organism, nervous and humoral regulation of various functions is carried out according to the principle of self-regulation, i.e. automatically. According to this principle of regulation, blood pressure, the constancy of the composition and physicochemical properties of blood, lymph and tissue fluid, body temperature are maintained at a certain level, metabolism, the activity of the heart, respiratory and other systems and organs change in a strictly coordinated manner.

Thanks to this, certain relatively constant conditions are maintained in which the activity of cells and tissues of the body takes place, or in other words, the constancy of the internal environment is maintained.

Thus, the human body is a single, integral, self-regulating and self-developing biological system that has certain reserve capabilities. At the same time, you need to know that the ability to perform physical and mental work can increase many times, without actually having any restrictions in its development.

The organism is a single whole. The unity of the body is ensured by a unified metabolism, a unified neuro-humoral regulation, and a common hemo- and lymphocirculation system for all tissues. The organism exists in close interaction with the environment, exchanging substances, energy, and information with it. The existence of an organism, relatively independent of the environment, is ensured by the body’s ability to maintain indicators of the internal environment at a constant level (homeostasis). The most important indicators of homeostasis include normal blood concentrations of minerals and nutrients, metabolites, hydrogen ions, blood cells and other indicators.

Physiological regulation is the control of body functions in order to adapt it to environmental conditions. Regulation of body functions is the basis for ensuring the constancy of the body’s internal environment and its adaptation to changing conditions of existence and is carried out on the principle of self-regulation through the formation of functional systems. The function of systems and the body as a whole is called activity aimed at preserving the integrity and properties of the system. Functions are characterized quantitatively and qualitatively.

The basis of physiological regulation is the transmission and processing of information. The term “information” refers to any message about facts and events occurring in the environment and the human body. Self-regulation is understood as this type of regulation when the deviation of the regulated parameter is a stimulus for its restoration.

To implement the principle of self-regulation, the interaction of the following components of functional systems is necessary:

Adjustable parameter (object of regulation, constant).

Control devices that monitor the deviation of this parameter under the influence of external and internal factors.

Regulatory devices that provide directed action on the activity of organs on which the restoration of the deviated parameter depends.

Execution apparatuses are organs and organ systems, changes in the activity of which in accordance with regulatory influences lead to the restoration of the original value of the parameter.

“Reverse afferentation carries information to the regulatory apparatuses about the achievement or failure to achieve a useful result, about the return or non-return of a deviated parameter to the norm. Thus, the regulation of functions is carried out by a system that consists of individual elements: a control device (CNS, endocrine cell), communication channels ( nerves, liquid internal environment), sensors that perceive the action of external and internal environmental factors (receptors), structures that perceive information from output channels (cell receptors) and executive organs.

The regulatory system in the body has a three-level structure. The first level of regulation consists of relatively autonomous local systems that maintain constants. The second level of the regulatory system provides adaptive reactions in connection with changes in the internal environment; at this level, the optimal operating mode of physiological systems is ensured for adapting the body to the external environment. The third level of regulation is implemented by the behavioral reactions of the body and ensures the optimization of its vital functions.

There are four types of regulation: mechanical, humoral, nervous, neurohumoral.

Physical (mechanical) regulation is realized through mechanical, electrical, optical, sound, electromagnetic, thermal and other processes (for example, filling the cavities of the heart with an additional volume of blood leads to a greater degree of stretching of their walls and to a stronger contraction of the myocardium). The most reliable regulatory mechanisms are local. They are realized through the physical and chemical interaction of organ structures. For example, in a working muscle, as a result of the release of chemical metabolites and heat by myocytes, dilation of blood vessels occurs, which is accompanied by an increase in the volumetric velocity of blood flow and an increase in the supply of myocytes with nutrients and oxygen. Local regulation can be carried out with the help of biologically active substances (histamine), tissue hormones (prostaglandins).

Humoral regulation carried out through the body's fluids (blood (humor), lymph, intercellular, cerebrospinal fluid) with the help of various biologically active substances that are secreted by specialized cells, tissues or organs. This type of regulation can be carried out at the level of organ structures - local self-regulation, or provide generalized effects through the hormonal regulation system. Chemical substances that are formed in specialized tissues and have specific functions enter the blood. Among these substances there are: metabolites, mediators, hormones. They can act locally or remotely.

For example, ATP hydrolysis products, the concentration of which increases with increasing functional activity of cells, cause dilation of blood vessels and improve the trophism of these cells. Hormones, the secretion products of special endocrine organs, play a particularly important role. The endocrine glands include: the pituitary gland, the thyroid and parathyroid glands, the islet apparatus of the pancreas, the adrenal cortex and medulla, the gonads, the placenta and the pineal gland.

Hormones influence metabolism, stimulate morphological processes, differentiation, growth, metamorphosis of cells, include certain activities of executive organs, change the intensity of activity of executive organs and tissues. The humoral pathway of regulation acts relatively slowly, the speed of the response depends on the rate of formation and secretion of the hormone, its penetration into the lymph and blood, and the speed of blood flow. The local effect of the hormone is determined by the presence of a specific receptor for it. The duration of action of the hormone depends on the rate of its destruction in the body. In various cells of the body, including the brain, neuropeptides are formed that affect the behavior of the body, a number of different functions and regulate the secretion of hormones.

Nervous regulation carried out through the nervous system, is based on the processing of information by neurons and its transmission along the nerves.

Has the following features:

Greater speed of development of action;

Communication accuracy;

High specificity - a strictly defined number of components needed at a given moment is involved in the reaction.

Nervous regulation is carried out quickly, with the direction of the signal to a specific addressee. The transmission of information (neuron action potentials) occurs at speeds of up to 80-120 m/s without a decrease in amplitude or loss of energy. Somatic and autonomic functions of the body are subject to nervous regulation. The basic principle of nervous regulation is reflex. The nervous mechanism of regulation phylogenetically arose later than the local and humoral ones and provides high accuracy, speed and reliability of the response. It is the most advanced regulatory mechanism.

Neurohumoral correlation.

In the process of evolution, the nervous and humoral types of correlations were combined into a neurohumoral form, when the urgent involvement of organs in the process of action through nervous correlation is supplemented and prolonged by humoral factors.

Nervous and humoral correlations play a leading role in the unification (integration) of the constituent parts (components) of the body into a single whole organism. At the same time, they seem to complement each other with their characteristics. The humoral connection is generalized. It is simultaneously implemented throughout the entire body. The nervous connection is directional in nature, it is the most selective and is realized in each specific case mainly at the level of certain components of the body.

Creative connections ensure the exchange of macromolecules between cells, which are capable of exerting a regulatory influence on the processes of metabolism, differentiation, growth, development, and functioning of cells and tissues. Through creative connections, the influence of kalons is exerted - proteins that suppress the synthesis of nucleic acids and cell division.

Metabolites, through a feedback mechanism, influence intracellular metabolism and cell functions and the functioning of nearby structures. For example, during intense muscular work, lactic and pyruvic acids, formed in the muscle cell under conditions of oxygen deficiency, lead to the expansion of muscle microvessels, to an increase in the flow of blood, nutrients and oxygen, which improves the nutrition of muscle cells. At the same time, they stimulate the metabolic pathways of their use and reduce muscle contractility.

The neuroendocrine system ensures that the metabolic, physical functions and behavioral reactions of the body correspond to environmental conditions, supports the processes of differentiation, growth, development, and regeneration of cells; generally contribute to the preservation and development of both the individual and the biological species as a whole. Dual (nervous and endocrine) regulation ensures, through a duplication mechanism, the reliability of regulation, high speed of response through the nervous system and the duration of the response over time through the release of hormones.

Phylogenetically, the most ancient hormones are produced by nerve cells; a chemical signal and a nerve impulse are often interconvertible. Hormones, being neuromodulators, influence the effects of many mediators in the central nervous system (gastrin, cholecystokinin, VIP, GIP, neurotensin, bombesin, substance P, opiomelanocortins - ACTH, beta-, gamma-lipotropins, alpha-, beta-, gamma-endorphins, prolactin, somatotropin). Hormone-producing neurons have been described.

The basis of nervous and humoral regulation is the principle of a ring connection, which in biological systems was primarily shown by the Soviet physiologist P.K. Anokhin. Positive and negative feedback ensures an optimal level of functioning - strengthening weak responses and limiting over-strong ones.

The division of regulatory mechanisms into nervous and humoral is conditional.

In the body, these mechanisms are inseparable:

1) Information about the state of the external and internal environment, as a rule, is perceived by elements of the nervous system, and after processing in neurons, both nervous and humoral regulatory pathways can be used as executive organs.

2) The activity of the endocrine glands is controlled by the nervous system. In turn, the metabolism, development and differentiation of neurons is carried out under the influence of hormones.

3) Action potentials at the points of contact between the neuron and the working cell cause the secretion of a mediator, which, through the humoral link, changes the function of the cell. Thus, in the body there is a unified neurohumoral regulation with priority significance of the nervous system. The body responds to the action of each stimulus with a complex biological reaction as a whole. This is achieved by the interaction of all systems, tissues and cells of the body. The interaction is ensured by local, humoral and neural regulatory mechanisms

The human nervous system is divided into central (brain and spinal cord) and peripheral. The central nervous system ensures the individual adaptation of the body to its environment, adaptation of the body, behavior of the body in accordance with the constitution and its needs, ensures the integration and unification of organs into a single whole based on the perception, evaluation, comparison, analysis of information coming from the external and internal environment of the body . The peripheral nervous system provides tissue trophism and has a direct impact on the structure and functional activity of organs.

The organism as a whole in changing environmental conditions. See Neurohumoral regulation.

Big Encyclopedic Dictionary. 2000 .

See what “NERVOUS REGULATION” is in other dictionaries:

The coordinating influence of the nervous system (NS) on cells, tissues and organs, bringing their activities into line with the needs of the body and changes in the environment; one of the main mechanisms of self-regulation of functions. Multicellular organism... ... Wikipedia

The coordinating influence of the nervous system on cells, tissues and organs, bringing their activity into line with the needs of the body and changes in the environment. N. r. has a leading role in ensuring the integrity of the body and is... ... Biological encyclopedic dictionary

The regulatory effect of the nervous system on tissues, organs and their systems, ensuring the consistency of their activities and the normal existence of the organism as a whole in changing environmental conditions. See Neurohumoral regulation. * * * NERVOUS… … Encyclopedic Dictionary

neural regulation- nervinis reguliavimas statusas T sritis Kūno kultūra ir sportas apibrėžtis Nervų sistemos veikla, koordinuojanti fiziologinius organizmo vyksmus. atitikmenys: engl. nervous regulation vok. Nervenregulation, f rus. nervous regulation...Sporto terminų žodynas

The coordinating influence of the nervous system (NS) on cells, tissues and organs, bringing their activities into line with the needs of the body and changes in the environment; one of the main mechanisms of self-regulation (See Self-regulation) ... ... Great Soviet Encyclopedia

Regulatory influence of nerves. systems on tissues, organs and their systems, ensuring the consistency of their activities and the normal existence of the organism as a whole in changing environmental conditions. See Neurohumoral regulation... Natural science. Encyclopedic Dictionary

NERVOUS REGULATION- [from lat. regulare put in order, establish] the regulatory effect of the nervous system on tissues, organs and their systems, ensuring the consistency of their activities and the normal existence of the organism as a whole in changing environmental conditions... ... Psychomotorics: dictionary-reference book

nervous system- (from the Greek n e u gop nerve and sistema whole, made up of parts) the totality of all elements of the nervous tissue of living organisms, interconnected and providing a response to external and internal stimuli. N. s. provides... ... Great psychological encyclopedia

Filtering of sensory information; filtering of afferent signals by the nervous system. As a result of such filtering, only part of the sensory information received by previous levels is received at certain processing levels. In English... ... Wikipedia

A complex network of structures that permeates the entire body and ensures self-regulation of its vital functions due to the ability to respond to external and internal influences (stimuli). The main functions of the nervous system are receiving, storing and... Collier's Encyclopedia

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• Physiology and ethology of animals. Textbook and workshop. In 3 parts. Part 3. Endocrine and central nervous systems, higher nervous activity, analyzers, ethology, A. I. Enukashvili, A. B. Andreeva, T. A. Eisymont, This textbook is a presentation of the basic physiological functions of the body. Focusing on modern scientific data, the authors revealed the essence of the mechanisms of nervous, humoral and... Category: Veterinary Series: Vocational education Publisher: YURAYT, Manufacturer: YURAYT,
• Comparative physiology of animals (set of 3 books), A. I. Enukashvili, A. B. Andreeva, T. A. Eisymont, Fundamental guide to comparative physiology of animals; published in Russian in three volumes. The book successfully combines the advantages of a textbook and a reference book containing... Category: Zoology Publisher:

Reflex effect on the activity of the heart

Reflex regulation of cardiac activity ensures adaptation of the activity of the heart to the body.

• intracardiac reflexes;
• from interoreceptors;
• from exteroceptors.

The most pronounced effect is on the interoceptors of the cardiovascular system. Areas of accumulation are called reflexogenic zones.

Types of reflex influences

From the carotid sinuses.

Carotid sinuses are ampulla-shaped dilations of the carotid arteries at the site of bifurcation into internal and external.

There are 2 types of mechanoreceptors:

• 1st order – responds to increased pressure;
• 2nd order - react to a decrease in pressure.

When pressure increases, first-order mechanoreceptors are excited; from the carotid sinus, along the fibers of the IX pair of cranial nerves, impulses go to and excite the nerve nuclei. The frequency of these impulses is such that irradiation occurs to the nuclei of the X pair - the n.vagus is excited, the activity of the heart is inhibited. As a result, the strength and frequency of heart contractions decreases, less blood enters the vascular system per unit of time, and blood pressure decreases.

When blood pressure decreases, 2nd order mechanoreceptors are excited and transmitted to the nerves along the fibers of the IX pair of cranial nerves. The frequency of the impulses is such that the activity of the X pair of cranial nerves is inhibited, the influence of the sympathetic department begins to predominate - the frequency and strength of heart contractions increases - blood pressure increases.

Reflex influence from the aortic arch

The aortic arch is innervated by n.vagus fibers. The same receptors respond to both increased blood pressure and decreased blood pressure. But impulses of different frequency and amplitude arise.

Reflex influences from the right atrium

Bainbridge effect: when the right atrium is stretched, impulses go to the n.vagus nuclei, and activity is inhibited, which leads to an increase in heart rate.

Reflex influences of the pericardium

Chernigovsky - when the pericardium is stretched or its chemoreceptors are excited, inhibition of cardiac activity is observed.

Reflex influence from the vessels of the pulmonary circulation

Parin reflex - with an increase in blood pressure in the vessels of the small blood circle, inhibition of cardiac activity is observed.

Reflex influence of receptors at the mouths of the vena cavae

Bezalda-Jarisch reflex - with increased pressure in the vena cava, inhibition of cardiac activity is observed.

Reflexes from interoreceptors of internal organs - mainly the gastrointestinal tract. Goltz reflex - when the gastrointestinal tract is irritated, cardiac activity is inhibited (visceral-visceral reflex).

Reflexes from exteroceptors (mainly from the skin)

When pain receptors, cold receptors, and mucous membranes are irritated by sharp substances, the sympathetic nervous system is activated and tachycardia is observed.

Humoral regulation of heart activity

All substances acting on the heart are divided into substances of systemic and local action.

Systemic substances

Electrolytes: K+, Ca2+ (especially their ratio). If K+ > Ca2+ – cardiac inhibition (under the influence of K+ – hyperpolarization). If Ca2+ > K+ – an increase in the strength of heart contractions, a decrease in myocardial relaxation is possible. With an excess of Ca2+ - cardiac arrest in systole.

Hormones:

• adrenalin– sharply increases the frequency and strength of heart contractions. This is the hormone of extreme situations.
• thyroxine– stimulates cardiac activity, but acts continuously. It acts by stimulating oxidative phosphorylation. Increases the sensitivity of the heart to other hormones (adrenaline).
• mineralocorticoids (aldosterone)– increase the excretion of K+ from the body, Ca2+ begins to predominate – the force of heart contractions increases.
• sex hormones– stimulate cardiac activity.
• atrial hormones– Atrial cardiocytes produce substances with hormonal activity. These are regular peptides: cardiodyllatine, cardiosodium, natriuretic hormones (alpha, beta, gamma).

These substances are released into the blood when:

• increasing venous blood return;
• with increasing pressure in the vessels;
• with a decrease in Na+ in the blood;
• when the cavities of the heart are overflowing with blood.

These hormones stimulate the heart (increase the frequency and strength of heart contractions) - as a result, the heart quickly rids itself of blood: the minute volume increases; vascular tone decreases and vessels dilate, as a result - a decrease in pressure, filtration and reabsorption processes in the kidneys are stimulated, ensuring sodium retention and K+ excretion (electrolyte composition is restored).

Substances of local action:

• mediators: acetylcholine– slows down the heart; norepinephrine – stimulates;
• tissue hormones (kinins): bradykinins- slow down; prostaglandins E(1), F(1)– stimulate, prostaglandin F(2alpha)– inhibit cardiac activity;
• metabolites– in low concentrations they stimulate, in high concentrations they inhibit.

Humoral regulation– coordination of physiological and biochemical processes in the body, carried out through liquid media (blood, lymph, tissue fluid) with the help of hormones and various metabolic products. In highly developed animals and humans it is subordinated, together with which it forms a unified system of neurohumoral regulation. Humoral regulation, coordination of physiological and biochemical processes carried out through body fluids (blood, lymph, tissue fluid) with the help of biologically active substances (metabolites, hormones, hormonoid ions) secreted by cells, organs and tissues during their vital activity. In highly developed animals and humans, G. r. is subject to nervous regulation and, together with it, forms a unified system of neurohumoral regulation. Metabolic products act not only directly on effector organs, but also on the endings of sensory nerves (chemoreceptors) and, causing one or another through humoral or reflex pathways. So, if, as a result of intense physical work, the CO2 content in the blood increases, then this causes excitation of the respiratory center, which leads to an increase in and removal of excess CO2 from the body. Humoral transmission of nerve impulses by chemicals, so-called. mediators, carried out in the central and peripheral nervous system. Along with hormones, it plays an important role in G. birth. products of interstitial metabolism play. The biological activity of body fluids is determined by the ratio of the content of catecholamines (adrenaline and norepinephrine, their precursors and breakdown products), acetylcholine, histamine, serotonin and other biogenic amines, some polypeptides and amino acids, the state of enzyme systems, the presence of activators and inhibitors, the content of ions, microelements etc. The doctrine of G. r. developed by a number of domestic (V. Ya. Danilevsky, A. F. Samoilov, K. M. Bykov, L. S. Stern, etc.) and foreign scientists (Austrian - O. Löwy, American - W. Cannon, etc.) .

Nervous regulation , coordinating the influence of the nervous system (NS) on cells, tissues and organs, bringing their activities into line with the needs of the body and changes in the environment; one of the main mechanisms of self-regulation of functions. A multicellular organism in its vital manifestations (growth, development, reactions to external influences, etc.) acts as a single whole. This integrity is ensured by a number of regulatory mechanisms, among which nervous regulation has acquired leading importance in animals. As a result of nervous regulation, the activity of cells and organs can be initiated, stopped, strengthened, weakened; the functional and biochemical state of cells and organs, as well as the features of their structure, may change. In multicellular organisms that do not have a NS (plants, animal embryos, sponges), the orderliness of functions is ensured by intercellular interactions - ionic, metabolic, etc. The activity of some cells can be regulated by the metabolic products of other cells (see Humoral regulation). The excited state of the surface membrane that arises in any of the cells can sometimes spread, covering cell after cell (the so-called neuroid conduction - a process similar in its ionic mechanism to the conduction of a nerve impulse). On this basis, during the evolution of animals, 2 main coordinating mechanisms developed - nervous regulation and hormonal regulation. Accordingly, there are 2 types of mediator substances – mediators and hormones. The hormone spreads throughout the body, entering the blood; As a result, hormonal regulation is slow and widely targeted. In contrast, neural regulation can be rapid and local. This is ensured by the fact that during nervous regulation the transmitter is released from the nerve endings directly onto the innervated cells, and also by the fact that the release of the transmitter is caused by a rapidly spreading signal - a nerve impulse. There is no sharp boundary between nervous regulation and hormonal regulation; some nerve endings release active substances into the blood (see Neurosecretion). Speed ​​and targeting Nervous regulation is especially important in the regulation of movements, therefore the nervous system is well developed in organisms with perfect locomotion. Becoming the leading regulatory mechanism in the process of evolution, nervous regulation in higher animals covers not only the motor sphere, but also all other systems of the body. Under nervous control are both executive (effector) and sensitive (receptor) organs and cells, as well as all autonomic functions (see. Autonomic nervous system). Nervous regulation also extends to tissues that provide the metabolic needs of the body (for example, adipose tissue). In order for a mediator to act on a cell, it must be sensitive to it, i.e., have the appropriate receptors. Thus, in the skeletal muscle of vertebrates, on the surface of each muscle fiber there are so-called cholinergic receptors, which interact with the mediator of motor nerve endings - acetylcholine (see Motor plaque). As a result of the reaction between the mediator and the receptor, the ionic permeability of the surface membrane of the innervated cell changes. At the same time, the ionic composition of the cytoplasm and the membrane potential change, as a result of which the specific activity of the cell is enhanced or inhibited (see Membrane theory of excitation). Apparently, in some cases, the mediator can have a direct, not ion-mediated, effect on the metabolic processes of the cell (enzymo-chemical hypothesis of nervous excitation, put forward by Kh. S. Koshtoyants in 1950). The role of mediators in the effect of the NS on the growth and differentiation of organs and tissues, regeneration processes, and maintenance of a certain functional and biochemical state of innervated cells (trophic function of the NS; see Nervous trophism) is less clear. It is possible that in these forms of nervous regulation, proteins and other substances that are released from the nerve ending simultaneously with the mediator are important.

With physiological regulation of the body, functions are carried out at an optimal level for normal performance, maintaining homeostatic conditions with metabolic processes. Its goal is to ensure that the body is always adapted to changing environmental conditions.

In the human body, regulatory activity is represented by the following mechanisms:

• nervous regulation;

The work of nervous and humoral regulation is joint; they are closely related to each other. Chemical compounds that regulate the body affect neurons with a complete change in their state. Hormonal compounds secreted in the corresponding glands also affect the NS. And the functions of the glands that produce hormones are controlled by the NS, the importance of which in supporting the regulatory function for the body is enormous. The humoral factor is part of the neurohumoral regulation.

Examples of regulations

The clarity of regulation will show an example of how the osmotic pressure of the blood changes when a person is thirsty. This type of pressure increases due to a lack of moisture inside the body. This leads to irritation of osmotic receptors. The resulting excitement is transmitted through the nerve pathways to the central nervous system. From it, many impulses reach the pituitary gland, stimulation occurs with the release of antidiuretic pituitary hormone into the bloodstream. In the bloodstream, the hormone penetrates the curved renal canals, and the reabsorption of moisture from the glomerular ultrafiltrate (primary urine) into the bloodstream increases. The result of this is that there is a decrease in urine excreted with water, and the body’s osmotic pressure, which has deviated from normal levels, is restored.

When there is an excess glucose level in the blood flow, the nervous system stimulates the functions of the introsecretory region of the endocrine organ that produces insulin hormone. Already in the bloodstream, the supply of insulin hormone has increased, unnecessary glucose, due to its influence, passes to the liver and muscles in glycogen form. Intense physical work increases glucose consumption, its volume in the bloodstream decreases, and the functions of the adrenal glands are strengthened. Adrenaline hormone converts glycogen into glucose. Thus, nervous regulation affecting the intrasecretory glands stimulates or inhibits the functions of important active biological compounds.

Humoral regulation of the vital functions of the body, in contrast to nervous regulation, uses different fluid environments of the body when transferring information. Signal transmission is carried out using chemical compounds:

• hormonal;
• mediator;
• electrolytes and many others.

Humoral regulation, as well as nervous regulation, contains some differences.

• there is no specific addressee. The flow of biological substances is delivered to different cells of the body;
• information is delivered at a low speed, which is comparable to the flow speed of bioactive media: from 0.5-0.6 to 4.5-5 m/s;
• The action is long.

Nervous regulation of vital functions in the human body is carried out with the help of the central nervous system and the PNS. Signal transmission is carried out using numerous impulses.

This regulation is characterized by its differences.

• there is a specific address for signal delivery to a specific organ or tissue;
• information is delivered at high speed. Pulse speed ─ up to 115-119 m/s;
• the effect is short-term.

Humoral regulation

The humoral mechanism is an ancient form of interaction that has been improved over time. In humans, there are several different options for implementing this mechanism. The nonspecific regulation option is local.

Local cellular regulation is carried out by three methods, their basis is the transfer of signals by compounds within the boundaries of a single organ or tissue using:

• creative cell communication;
• simple types of metabolite;
• active biological compounds.

Thanks to the creative connection, intercellular information exchange occurs, which is necessary for the directed adjustment of the intracellular synthesis of protein molecules with other processes for the transformation of cells into tissues, differentiation, development with growth, and ultimately performing the functions of the cells contained in the tissue as an integral multicellular system.

A metabolite is a product of metabolic processes and can act autocrine, that is, change the cellular performance through which it is released, or paracrine, that is, change the cellular performance, where the cell is located within the border of the same tissue, reaching it through the intracellular fluid. For example, when lactic acid accumulates during physical work, the vessels bringing blood to the muscles dilate, the oxygen saturation of the muscle increases, however, the strength of muscle contractility decreases. This is how humoral regulation manifests itself.

Hormones located in tissues are also biologically active compounds - products of cell metabolism, but have a more complex chemical structure. They are presented:

• biogenic amines;
• kinins;
• angiotensins;
• prostaglandins;
• endothelium and other compounds.

These compounds change the following biophysical cellular properties:

• membrane permeability;
• setting up energy metabolic processes;
• membrane potential;
• enzyme reactions.

They also promote the formation of secondary messengers and change tissue blood supply.

BAS (biologically active substances) regulate cells using special cell-membrane receptors. BAS also modulate regulatory influences, since they change cellular sensitivity to nervous and hormonal influences by changing the number of cellular receptors and their similarity to various information-carrying molecules.

BAS, formed in different tissues, have an autocrine and paracrine effect, but are able to penetrate into the blood and act systemically. Some of them (kinins) are formed from precursors in the blood plasma, so these substances, when acted locally, even cause a widespread result similar to hormonal.

Physiological adjustment of body functions is carried out through the coordinated interaction of the nervous system and the humoral system. Nervous and humoral regulation combine the functions of the body for its full functionality, and the human body works as one.

The interaction of the human body with external environmental conditions is carried out with the help of an active nervous system, the performance of which is determined by reflexes.