Homeostasis in the classical sense of the word is a physiological concept that denotes the stability of the composition of the internal environment, the constancy of the components of its composition, as well as the balance of the biophysiological functions of any living organism.
The basis of such a biological function as homeostasis is the ability of living organisms and biological systems to resist environmental changes; while organisms use autonomous defense mechanisms.
For the first time this term was used by the physiologist, American W. Kennon at the beginning of the twentieth century.
Any biological object has universal parameters of homeostasis.
Homeostasis of the system and body
The scientific basis for such a phenomenon as homeostasis was formed by the Frenchman C. Bernard - it was a theory about the constant composition of the internal environment in the organisms of living beings. This scientific theory was formulated in the eighties of the eighteenth century and has been widely developed.
So, homeostasis is the result of a complex mechanism of interaction in the field of regulation and coordination, which occurs both in the body as a whole and in its organs, cells, and even at the molecular level.
The concept of homeostasis received an impetus for further development as a result of the use of cybernetics methods in the study of complex biological systems, such as a biocenosis or a population).
Functions of homeostasis
The study of objects with a feedback function has helped scientists learn about the many mechanisms responsible for their stability.
Even in conditions of serious changes, the mechanisms of adaptation (adaptation) do not allow the chemical and physiological properties of the organism to change greatly. It cannot be said that they remain absolutely stable, but serious deviations usually do not occur.
Mechanisms of homeostasis
The mechanism of homeostasis in organisms is most well developed in higher animals. In the organisms of birds and mammals (including humans), the function of homeostasis allows you to maintain the stability of the number of hydrogen ions, regulates the constancy of the chemical composition of the blood, keeps the pressure in the circulatory system and body temperature at about the same level.
There are several ways in which homeostasis affects organ systems and the body as a whole. This can be an effect with the help of hormones, the nervous system, excretory or neuro-humoral systems of the body.
Human homeostasis
For example, the stability of pressure in the arteries is maintained by a regulatory mechanism that works in the manner of chain reactions that the blood organs enter into.
This happens in such a way that the vascular receptors feel the change in the pressure force and transmit a signal about this to the human brain, which sends response impulses to the vascular centers. The consequence of this is an increase or decrease in the tone of the circulatory system (heart and blood vessels).
In addition, the organs of neuro-humoral regulation come into play. As a result of this reaction, the pressure returns to normal.
Ecosystem homeostasis
An example of homeostasis in the plant world is the preservation of constant leaf moisture by opening and closing stomata.
Homeostasis is also characteristic of communities of living organisms of any degree of complexity; for example, the fact that a relatively stable composition of species and individuals is preserved within the biocenosis is a direct consequence of the action of homeostasis.
Population homeostasis
Such a type of homeostasis as population (its other name is genetic) plays the role of a regulator of the integrity and stability of the genotypic composition of a population in a changing environment.
It acts through the preservation of heterozygosity, as well as by controlling the rhythm and direction of mutational changes.
This type of homeostasis allows the population to maintain the optimal genetic composition, which allows the community of living organisms to maintain maximum viability.
The role of homeostasis in society and ecology
The need to manage complex systems of a social, economic and cultural nature has led to the expansion of the term homeostasis and its application not only to biological, but also to social objects.
The following situation can serve as an example of the work of homeostatic social mechanisms: if there is a lack of knowledge or skills or a professional shortage in society, then through the feedback mechanism this fact makes the community develop and improve itself.
And in the case of an excess number of professionals who are actually not in demand by society, there will be a negative feedback and there will be fewer representatives of unnecessary professions.
Recently, the concept of homeostasis has found wide application in ecology, due to the need to study the state of complex ecological systems and the biosphere as a whole.
In cybernetics, the term homeostasis is used in relation to any mechanism that has the ability to automatically self-regulate.
Links related to homeostasis
Homeostasis on Wikipedia.2. Learning goals:
Know the essence of homeostasis, the physiological mechanisms of maintaining homeostasis, the basics of homeostasis regulation.
To study the main types of homeostasis. Know the age-related features of homeostasis
3. Questions for self-preparation for mastering this topic:
1) Definition of the concept of homeostasis
2) Types of homeostasis.
3) Genetic homeostasis
4) Structural homeostasis
5) Homeostasis of the internal environment of the body
6) Immunological homeostasis
7) Mechanisms of regulation of homeostasis: neurohumoral and endocrine.
8) Hormonal regulation of homeostasis.
9) Organs involved in the regulation of homeostasis
10) General principle of homeostatic reactions
11) Species specificity of homeostasis.
12) Age-related features of homeostasis
13) Pathological processes, accompanied by a violation of homeostasis.
14) Correction of the homeostasis of the body is the main task of the doctor.
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4. Type of lesson: extracurricular
5. Duration of the lesson- 3 hours.
6. Equipment. Electronic presentation "Lectures on biology", tables, dummies
homeostasis(gr. homoios - equal, stasis - state) - the property of an organism to maintain the constancy of the internal environment and the main features of its inherent organization, despite the variability of the parameters of the external environment and the action of internal disturbing factors.
The homeostasis of each individual is specific and determined by its genotype.
The body is an open dynamic system. The flow of substances and energy observed in the body determines self-renewal and self-reproduction at all levels from molecular to organismic and population.
In the process of metabolism with food, water, during gas exchange, a variety of chemical compounds enter the body from the environment, which, after transformations, are likened to the chemical composition of the body and are included in its morphological structures. After a certain period, the absorbed substances are destroyed, releasing energy, and the destroyed molecule is replaced by a new one, without violating the integrity of the structural components of the body.
Organisms are in a constantly changing environment, despite this, the main physiological indicators continue to be carried out in certain parameters and the body maintains a stable state of health for a long time, thanks to self-regulation processes.
Thus, the concept of homeostasis is not related to the stability of processes. In response to the action of internal and external factors, some change in physiological parameters occurs, and the inclusion of regulatory systems ensures the maintenance of a relative constancy of the internal environment. Regulatory homeostatic mechanisms function at the cellular, organ, organismic and supraorganismal levels.
In evolutionary terms, homeostasis is a hereditarily fixed adaptation of an organism to normal environmental conditions.
There are the following main types of homeostasis:
1) genetic
2) structural
3) homeostasis of the liquid part of the internal environment (blood, lymph, interstitial fluid)
4) immunological.
Genetic homeostasis- preservation of genetic stability due to the strength of the physicochemical bonds of DNA and its ability to recover after damage (DNA repair). Self-reproduction is a fundamental property of the living, it is based on the process of DNA reduplication. The very mechanism of this process, in which a new DNA strand is built strictly complementary around each of the constituent molecules of the two old strands, is optimal for accurate information transfer. The accuracy of this process is high, but reduplication errors can still occur. Violation of the structure of DNA molecules can also occur in its primary chains without regard to reduplication under the influence of mutagenic factors. In most cases, the cell genome is restored, the damage is corrected, due to repair. When repair mechanisms are damaged, genetic homeostasis is disrupted both at the cellular and organismal levels.
An important mechanism for maintaining genetic homeostasis is the diploid state of somatic cells in eukaryotes. Diploid cells are more stable in functioning, because the presence of two genetic programs in them increases the reliability of the genotype. Stabilization of the complex system of the genotype is provided by the phenomena of polymerization and other types of gene interaction. Regulatory genes that control the activity of operons play an important role in the process of homeostasis.
Structural homeostasis- this is the constancy of the morphological organization at all levels of biological systems. It is advisable to single out the homeostasis of a cell, tissue, organ, body systems. The homeostasis of the underlying structures ensures the morphological constancy of the higher structures and is the basis of their vital activity.
The cell, as a complex biological system, is inherent in self-regulation. The establishment of homeostasis of the cellular environment is provided by membrane systems, which are associated with bioenergetic processes and regulation of the transport of substances into and out of the cell. In the cell, the processes of change and restoration of organelles are continuously going on, the cells themselves are destroyed and restored. Restoration of intracellular structures, cells, tissues, organs in the course of the life of the organism occurs due to physiological regeneration. Restoration of structures after damage - reparative regeneration.
Homeostasis of the liquid part of the internal environment- the constancy of the composition of blood, lymph, tissue fluid, osmotic pressure, the total concentration of electrolytes and the concentration of individual ions, the content of nutrients in the blood, etc. These indicators, even with significant changes in environmental conditions, are kept at a certain level, thanks to complex mechanisms.
For example, one of the most important physicochemical parameters of the internal environment of the body is the acid-base balance. The ratio of hydrogen and hydroxide ions in the internal environment depends on the content in body fluids (blood, lymph, tissue fluid) of acids - proton donors and buffer bases - proton acceptors. Usually, the active reaction of the medium is evaluated by the H+ ion. The pH value (the concentration of hydrogen ions in the blood) is one of the stable physiological indicators and varies in humans within narrow limits - from 7.32 to 7.45. The activity of a number of enzymes, membrane permeability, protein synthesis processes, etc. largely depend on the ratio of hydrogen and hydroxyl ions.
The body has various mechanisms that ensure the maintenance of acid-base balance. Firstly, these are the buffer systems of blood and tissues (carbonate, phosphate buffers, tissue proteins). Hemoglobin also has buffering properties, it binds carbon dioxide and prevents its accumulation in the blood. The activity of the kidneys also contributes to the maintenance of a normal concentration of hydrogen ions, since a significant amount of acidic metabolites is excreted in the urine. If these mechanisms are insufficient, the concentration of carbon dioxide in the blood increases, there is some shift in pH to the acid side. In this case, the respiratory center is excited, pulmonary ventilation is enhanced, which leads to a decrease in the content of carbon dioxide and the normalization of the concentration of hydrogen ions.
The sensitivity of tissues to changes in the internal environment is different. So a pH shift of 0.1 in one direction or another from the norm leads to significant disturbances in the activity of the heart, and a deviation of 0.3 is life-threatening. The nervous system is particularly sensitive to low oxygen levels. For mammals, fluctuations in the concentration of calcium ions exceeding 30% are dangerous, etc.
Immunological homeostasis- maintaining the constancy of the internal environment of the body by maintaining the antigenic individuality of the individual. Immunity is understood as a way of protecting the body from living bodies and substances bearing signs of genetically alien information (Petrov, 1968).
Bacteria, viruses, protozoa, helminths, proteins, cells, including altered cells of the organism itself, carry alien genetic information. All of these factors are antigens. Antigens are substances that, when introduced into the body, are capable of causing the production of antibodies or another form of immune response. Antigens are very diverse, most often they are proteins, but these are also large molecules of lipopolysaccharides, nucleic acids. Inorganic compounds (salts, acids), simple organic compounds (carbohydrates, amino acids) cannot be antigens, because have no specificity. The Australian scientist F. Burnet (1961) formulated the position that the main significance of the immune system is the recognition of "own" and "foreign", i.e. in maintaining the constancy of the internal environment - homeostasis.
The immune system has a central (red bone marrow, thymus gland) and a peripheral (spleen, lymph nodes) link. The protective reaction is carried out by lymphocytes formed in these organs. Type B lymphocytes, when they encounter foreign antigens, differentiate into plasma cells that secrete specific proteins, immunoglobulins (antibodies), into the blood. These antibodies, connecting with the antigen, neutralize them. This reaction is called humoral immunity.
T-type lymphocytes provide cellular immunity by destroying foreign cells, such as transplant rejection, and mutated cells of their own body. According to the calculations given by F. Burnet (1971), in each genetic change of dividing human cells, about 10 - 6 spontaneous mutations accumulate within one day, i.e. at the cellular and molecular levels, processes that disrupt homeostasis are continuously occurring. T-lymphocytes recognize and destroy mutant cells of their own body, thus ensuring the function of immune surveillance.
The immune system controls the genetic constancy of the organism. This system, consisting of anatomically separated organs, represents a functional unity. The property of immune defense has reached its highest development in birds and mammals.
homeostasis regulation carried out by the following organs and systems (Fig. 91):
1) central nervous system;
2) neuroendocrine system, which includes the hypothalamus, pituitary gland, peripheral endocrine glands;
3) diffuse endocrine system (DES), represented by endocrine cells located in almost all tissues and organs (heart, lung, gastrointestinal tract, kidneys, liver, skin, etc.). The bulk of DES cells (75%) is concentrated in the epithelium of the digestive system.
It is now known that a number of hormones are simultaneously present in the central nervous structures and endocrine cells of the gastrointestinal tract. So the hormones enkephalins and endorphins are found in nerve cells and endocrine cells of the pancreas and stomach. Cholecystokinin was found in the brain and duodenum. Such facts gave grounds for creating a hypothesis about the presence in the body of a single system of cells of chemical information. The peculiarity of nervous regulation is the speed of the onset of the response, and its effect manifests itself directly in the place where the signal arrives along the corresponding nerve; reaction is short.
In the endocrine system, regulatory influences are associated with the action of hormones carried with the blood throughout the body; the effect of the action is long-lasting and does not have a local character.
The unification of the nervous and endocrine mechanisms of regulation occurs in the hypothalamus. The general neuroendocrine system allows for complex homeostatic reactions associated with the regulation of the visceral functions of the body.
The hypothalamus also has glandular functions, producing neurohormones. Neurohormones, getting into the anterior lobe of the pituitary gland with blood, regulate the release of tropic hormones of the pituitary gland. Tropic hormones directly regulate the work of the endocrine glands. For example, thyroid-stimulating hormone from the pituitary stimulates the thyroid gland by increasing the level of thyroid hormone in the blood. When the concentration of the hormone rises above the norm for a given organism, the thyroid-stimulating function of the pituitary gland is inhibited and the activity of the thyroid gland is weakened. Thus, to maintain homeostasis, it is necessary to balance the functional activity of the gland with the concentration of the hormone in the circulating blood.
This example shows the general principle of homeostatic reactions: deviation from the initial level --- signal --- activation of regulatory mechanisms on the feedback principle --- correction of change (normalization).
Some endocrine glands are not directly dependent on the pituitary gland. These are the pancreatic islets that produce insulin and glucagon, the adrenal medulla, the pineal gland, the thymus, and the parathyroid glands.
The thymus occupies a special position in the endocrine system. It produces hormone-like substances that stimulate the formation of T-lymphocytes, and a relationship is established between immune and endocrine mechanisms.
The ability to maintain homeostasis is one of the most important properties of a living system that is in a state of dynamic equilibrium with environmental conditions. The ability to maintain homeostasis is not the same in different species, it is high in higher animals and humans, which have complex nervous, endocrine and immune mechanisms of regulation.
In ontogeny, each age period is characterized by the peculiarities of metabolism, energy and mechanisms of homeostasis. In the child's body, the processes of assimilation prevail over dissimilation, which causes growth, an increase in body weight, the mechanisms of homeostasis are not yet mature enough, which leaves an imprint on the course of both physiological and pathological processes.
With age, there is an improvement in metabolic processes, regulatory mechanisms. In adulthood, the processes of assimilation and dissimilation, the system of normalization of homeostasis provide compensation. With aging, the intensity of metabolic processes decreases, the reliability of regulatory mechanisms weakens, the function of a number of organs fades, and at the same time new specific mechanisms develop that support the preservation of relative homeostasis. This is expressed, in particular, in an increase in the sensitivity of tissues to the action of hormones, along with a weakening of nervous influences. During this period, adaptive features are weakened, therefore, an increase in load and stressful conditions can easily disrupt homeostatic mechanisms and often become the cause of pathological conditions.
Knowledge of these patterns is necessary for a future doctor, since the disease is a consequence of a violation of the mechanisms and ways of restoring homeostasis in humans.
Homeostasis, homeostasis (homeostasis; Greek homoios similar, the same + stasis state, immobility), is the relative dynamic constancy of the internal environment (blood, lymph, tissue fluid) and the stability of basic physiological functions (blood circulation, respiration, thermoregulation, metabolism and etc.) of the human and animal organisms. Regulatory mechanisms that maintain the physiological state or properties of cells, organs and systems of the whole organism at an optimal level are called homeostatic.
As you know, a living cell is a mobile, self-regulating system. Its internal organization is supported by active processes aimed at limiting, preventing or eliminating shifts caused by various influences from the environment and the internal environment. The ability to return to the original state after a deviation from a certain average level, caused by one or another "disturbing" factor, is the main property of the cell. A multicellular organism is a holistic organization, the cellular elements of which are specialized to perform various functions. Interaction within the body is carried out by complex regulatory, coordinating and correlating mechanisms with
participation of nervous, humoral, metabolic and other factors. Many individual mechanisms that regulate intra- and intercellular relationships, in some cases, have mutually opposite (antagonistic) effects that balance each other. This leads to the establishment of a mobile physiological background (physiological balance) in the body and allows the living system to maintain relative dynamic constancy, despite changes in the environment and shifts that occur during the life of the organism.
The term "homeostasis" was proposed in 1929 by the physiologist W. Cannon, who believed that the physiological processes that maintain stability in the body are so complex and diverse that it is advisable to combine them under the general name of homeostasis. However, back in 1878, K. Bernard wrote that all life processes have only one goal - to maintain the constancy of living conditions in our internal environment. Similar statements are found in the works of many researchers of the 19th and the first half of the 20th century. (E. Pfluger, S. Richet, L.A. Fredericq, I.M. Sechenov, I.P. Pavlov, K.M. Bykov and others). The works of L.S. Stern (with collaborators), devoted to the role of barrier functions that regulate the composition and properties of the microenvironment of organs and tissues.
The very concept of homeostasis does not correspond to the concept of a stable (non-fluctuating) balance in the body - the principle of balance is not applicable to
complex physiological and biochemical
processes in living systems. It is also wrong to oppose homeostasis to rhythmic fluctuations in the internal environment. Homeostasis in a broad sense covers the issues of cyclic and phase flow of reactions, compensation, regulation and self-regulation of physiological functions, the dynamics of the interdependence of nervous, humoral and other components of the regulatory process. The boundaries of homeostasis can be rigid and plastic, vary depending on individual age, gender, social, professional and other conditions.
Of particular importance for the life of the organism is the constancy of the composition of the blood - the liquid basis of the body (fluid matrix), according to W. Cannon. The stability of its active reaction (pH), osmotic pressure, ratio of electrolytes (sodium, calcium, chlorine, magnesium, phosphorus), glucose content, number of formed elements, and so on are well known. So, for example, blood pH, as a rule, does not go beyond 7.35-7.47. Even severe disorders of acid-base metabolism with a pathology of acid accumulation in the tissue fluid, for example, in diabetic acidosis, have very little effect on the active reaction of the blood. Despite the fact that the osmotic pressure of blood and tissue fluid is subject to continuous fluctuations due to the constant supply of osmotically active products of interstitial metabolism, it remains at a certain level and changes only in some severe pathological conditions.
Despite the fact that blood represents the general internal environment of the body, the cells of organs and tissues do not directly come into contact with it.
In multicellular organisms, each organ has its own internal environment (microenvironment) corresponding to its structural and functional features, and the normal state of organs depends on the chemical composition, physicochemical, biological and other properties of this microenvironment. Its homeostasis is determined by the functional state of histohematic barriers and their permeability in the directions of blood→tissue fluid, tissue fluid→blood.
Of particular importance is the constancy of the internal environment for the activity of the central nervous system: even minor chemical and physicochemical shifts that occur in the cerebrospinal fluid, glia, and pericellular spaces can cause a sharp disruption in the course of life processes in individual neurons or in their ensembles. A complex homeostatic system, including various neurohumoral, biochemical, hemodynamic and other regulatory mechanisms, is the system for ensuring the optimal level of blood pressure. At the same time, the upper limit of the level of arterial pressure is determined by the functionality of the baroreceptors of the vascular system of the body, and the lower limit is determined by the body's needs for blood supply.
The most perfect homeostatic mechanisms in the body of higher animals and humans include the processes of thermoregulation;
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The term "homeostasis" is most commonly used in biology. For multicellular organisms to exist, it is necessary to maintain the constancy of the internal environment. Many ecologists are convinced that this principle also applies to the external environment. If the system is unable to restore its balance, it may eventually cease to function.
Complex systems - for example, the human body - must have homeostasis in order to maintain stability and exist. These systems not only have to strive to survive, they also have to adapt to environmental changes and evolve.
properties of homeostasis
Homeostatic systems have the following properties:
- instability system: tests how it can best adapt.
- Striving for balance: all the internal, structural and functional organization of systems contributes to maintaining balance.
- unpredictability: The resultant effect of a certain action can often be different from what was expected.
- Regulation of the amount of micronutrients and water in the body - osmoregulation. Carried out in the kidneys.
- Removal of waste products of the metabolic process - isolation. It is carried out by exocrine organs - kidneys, lungs, sweat glands and gastrointestinal tract.
- Body temperature regulation. Lowering the temperature through sweating, a variety of thermoregulatory reactions.
- Regulation of blood glucose levels. It is mainly carried out by the liver, insulin and glucagon secreted by the pancreas.
- Regulation of the level of basic metabolism depending on the diet.
It is important to note that although the body is in balance, its physiological state can be dynamic. Many organisms exhibit endogenous changes in the form of circadian, ultradian, and infradian rhythms. So, even while in homeostasis, body temperature, blood pressure, heart rate and most metabolic indicators are not always at a constant level, but change over time.
Mechanisms of homeostasis: feedback
When there is a change in variables, there are two main types of feedback that the system responds to:
- Negative feedback, expressed in a reaction in which the system responds in such a way as to change the direction of change to the opposite. Since the feedback serves to maintain the constancy of the system, it allows you to maintain homeostasis.
- For example, when the concentration of carbon dioxide in the human body increases, the lungs receive a signal to increase their activity and exhale more carbon dioxide.
- Thermoregulation is another example of negative feedback. When body temperature rises (or falls), thermoreceptors in the skin and hypothalamus register the change, triggering a signal from the brain. This signal, in turn, causes a response - a decrease in temperature (or increase).
- Positive feedback, which is expressed as an increase in the change in a variable. It has a destabilizing effect, so it does not lead to homeostasis. Positive feedback is less common in natural systems, but also has its uses.
- For example, in nerves, a threshold electrical potential causes the generation of a much larger action potential. Blood clotting and birth events are other examples of positive feedback.
Stable systems need combinations of both types of feedback. While negative feedback allows you to return to a homeostatic state, positive feedback is used to move to a completely new (and quite possibly less desirable) state of homeostasis, a situation called "metastability". Such catastrophic changes can occur, for example, with an increase in nutrients in rivers with clear water, which leads to a homeostatic state of high eutrophication (algae overgrowth of the channel) and turbidity.
Ecological homeostasis
In disturbed ecosystems, or subclimax biological communities - like, for example, the island of Krakatoa, after a strong volcanic eruption in - the state of homeostasis of the previous forest climax ecosystem was destroyed, like all life on this island. Krakatoa went through a chain of ecological changes in the years following the eruption, in which new plant and animal species succeeded each other, which led to biodiversity and, as a result, a climax community. Ecological succession in Krakatoa took place in several stages. A complete chain of successions leading to a climax is called a preserie. In the example of Krakatau, this island developed a climax community with eight thousand different species recorded in , a hundred years after the eruption destroyed life on it. The data confirm that the position is maintained in homeostasis for some time, while the emergence of new species very quickly leads to the rapid disappearance of old ones.
The case of Krakatoa and other disturbed or intact ecosystems shows that the initial colonization by pioneer species occurs through positive feedback reproduction strategies in which the species disperse, producing as many offspring as possible, but with little or no investment in the success of each individual. . In such species, there is a rapid development and an equally rapid collapse (for example, through an epidemic). As an ecosystem approaches climax, such species are replaced by more complex climax species that adapt through negative feedback to the specific conditions of their environment. These species are carefully controlled by the potential capacity of the ecosystem and follow a different strategy - the production of smaller offspring, in the reproductive success of which in the conditions of the microenvironment of its specific ecological niche, more energy is invested.
Development begins with the pioneer community and ends with the climax community. This climax community is formed when flora and fauna come into balance with the local environment.
Such ecosystems form heterarchies, in which homeostasis at one level contributes to homeostatic processes at another complex level. For example, the loss of leaves on a mature tropical tree makes room for new growth and enriches the soil. Equally, the tropical tree reduces the access of light to lower levels and helps prevent other species from invading. But trees also fall to the ground and the development of the forest depends on the constant change of trees, the cycle of nutrients carried out by bacteria, insects, fungi. Similarly, such forests contribute to ecological processes, such as the regulation of microclimates or ecosystem hydrological cycles, and several different ecosystems may interact to maintain river drainage homeostasis within a biological region. The variability of bioregions also plays a role in the homeostatic stability of a biological region, or biome.
Biological homeostasis
Homeostasis acts as a fundamental characteristic of living organisms and is understood as maintaining the internal environment within acceptable limits.
The internal environment of the body includes body fluids - blood plasma, lymph, intercellular substance and cerebrospinal fluid. Maintaining the stability of these fluids is vital for organisms, while its absence leads to damage to the genetic material.
With regard to any parameter, organisms are divided into conformational and regulatory. Regulatory organisms keep the parameter at a constant level, regardless of what happens in the environment. Conformational organisms allow the environment to determine the parameter. For example, warm-blooded animals maintain a constant body temperature, while cold-blooded animals exhibit a wide temperature range.
We are not talking about the fact that conformational organisms do not have behavioral adaptations that allow them to regulate the given parameter to some extent. Reptiles, for example, often sit on heated rocks in the morning to raise their body temperature.
The advantage of homeostatic regulation is that it allows the body to function more efficiently. For example, cold-blooded animals tend to become lethargic in cold temperatures, while warm-blooded animals are almost as active as ever. On the other hand, regulation requires energy. The reason why some snakes can only eat once a week is that they use much less energy to maintain homeostasis than mammals.
Cellular homeostasis
Regulation of the chemical activity of the cell is achieved through a number of processes, among which the change in the structure of the cytoplasm itself, as well as the structure and activity of enzymes, is of particular importance. Autoregulation depends on
The concept was introduced by the American psychologist W.B. Cannon in relation to any processes that change the initial state or a series of states, initiating new processes aimed at restoring the initial conditions. The mechanical homeostat is the thermostat. The term is used in physiological psychology to describe a number of complex mechanisms operating in the autonomic nervous system to regulate factors such as body temperature, biochemistry, blood pressure, fluid balance, metabolism, and so on. for example, a change in body temperature initiates a variety of processes such as shivering, increasing metabolism, increasing or retaining heat until normal temperature is reached. Examples of homeostatic psychological theories are balance theory (Heider, 1983), congruence theory (Osgood, Tannenbaum, 1955), cognitive dissonance theory (Festinger, 1957), symmetry theory (Newcomb, 1953), etc. As an alternative to the homeostatic approach, a heterostatic approach is proposed. an approach that assumes the fundamental possibility of the existence of balance states within a single whole (see heterostasis).
HOMEOSTASIS
Homeostasis) - maintaining a balance between opposing mechanisms or systems; the basic principle of physiology, which should also be considered the basic law of mental behavior.
HOMEOSTASIS
homeostasis The tendency of organisms to maintain their permanent state. According to Cannon (1932), the originator of the term: "Organisms, composed of matter characterized by the highest degree of variability and instability, have somehow mastered the means of maintaining permanence and maintaining stability under conditions that should reasonably be regarded as absolutely destructive." Freud's PLEASURE PRINCIPLE and Fechner's CONSTANT PRINCIPLE used by him are usually considered as psychological concepts analogous to the physiological concept of homeostasis, i.e. they suggest that there is a programmed tendency to maintain psychological VOLTAGE at a constant optimal level, similar to the tendency for the body to maintain a constant blood chemistry, temperature, etc.
HOMEOSTASIS
a mobile equilibrium state of a system, maintained by its counteraction to disturbing external and internal factors. Maintaining the constancy of various physiological parameters of the body. The concept of homeostasis was originally developed in physiology to explain the constancy of the internal environment of the body and the stability of its basic physiological functions. This idea was developed by the American physiologist W. Cannon in his doctrine of the wisdom of the body as an open system that continuously maintains stability. Receiving signals about changes that threaten the system, the body turns on devices that continue to work until it is possible to return it to an equilibrium state, to the previous values of the parameters. The principle of homeostasis passed from physiology to cybernetics and other sciences, including psychology, acquiring a more general meaning of the principle of a systematic approach and self-regulation based on feedback. The idea that every system strives to maintain stability was transferred to the interaction of the organism with the environment. Such a transfer is typical, in particular:
1) for neobehaviorism, which believes that a new motor reaction is fixed due to the release of the body from a need that has violated its homeostasis;
2) for the concept of J. Piaget, who believes that mental development occurs in the process of balancing the body with the environment;
3) for K. Levin's field theory, according to which motivation arises in a non-equilibrium "system of stresses";
4) for Gestalt psychology, which notes that if the balance of the components of the mental system is disturbed, it seeks to restore it. However, the principle of homeostasis, explaining the phenomenon of self-regulation, cannot reveal the source of changes in the psyche and its activity.
HOMEOSTASIS
Greek homeios - similar, similar, statis - standing, immobility). The mobile, but stable balance of any system (biological, mental), due to its opposition to internal and external factors that violate this balance (see Cannon's thalamic theory of emotions. The principle of G. is widely used in physiology, cybernetics, psychology, it explains the adaptive ability Mental G. maintains optimal conditions for the functioning of the brain and nervous system in the process of life.
HOMEOSTASIS(IS)
from the Greek homoios - similar + stasis - standing; letters, meaning "to be in the same state").
1. In the narrow (physiological) sense, G. - the processes of maintaining the relative constancy of the main characteristics of the internal environment of the body (for example, the constancy of body temperature, blood pressure, blood sugar, etc.) in a wide range of environmental conditions. A large role in G. is played by the joint activity of the vegetative n. c, hypothalamus and brain stem, as well as the endocrine system, while partly neurohumoral regulation G. It is carried out "autonomously" from the psyche and behavior. The hypothalamus "decides" at what G.'s violation it is necessary to turn to the highest forms of adaptation and start the mechanism of biological motivation of behavior (see the Drive reduction hypothesis, Needs).
The term "G." introduced Amer. physiologist Walter Cannon (Cannon, 1871-1945) in 1929, however, the concept of the internal environment and the concept of its constancy were developed much earlier than fr. physiologist Claude Bernard (Bernard, 1813-1878).
2. In a broad sense, the concept of "G." apply to a variety of systems (biocenoses, populations, individuals, social systems, etc.). (B. M.)
homeostasis
homeostasis) In order to survive and move freely in changing and often hostile environmental conditions, complex organisms need to maintain their internal environment relatively constant. This inner constancy was called "G" by Walter B. Cannon. Cannon described his findings as examples of steady state maintenance in open systems. In 1926, he proposed the term "G" for such a steady state. and proposed a system of postulates concerning its nature, which was subsequently expanded in preparation for the publication of a review of the homeostatic and regulatory mechanisms known by that time. The organism, Cannon argued, through homeostatic reactions is able to maintain the stability of the intercellular fluid (fluid matrix), thus controlling and regulating. body temperature, blood pressure, and other parameters of the internal environment, the maintenance of which within certain limits is necessary for life. G. tzh is maintained in relation to the levels of supply of substances necessary for the normal functioning of cells. The concept of G. proposed by Kennon appeared in the form of a set of provisions concerning the existence, nature and principles of self-regulating systems. He emphasized that complex living beings are open systems formed from changing and unstable components, constantly subject to perturbing external influences due to this openness. Thus, these ever-changing systems must nevertheless maintain constancy with respect to the environment in order to maintain conditions favorable to life. Correction in such systems should occur continuously. Therefore, G. characterizes rather than an absolutely stable state. The concept of an open system has challenged all traditional notions of an adequate unit of organism analysis. If the heart, lungs, kidneys, and blood, for example, are parts of a self-regulating system, then their action or function cannot be understood from a study of each of them individually. A full understanding is possible only on the basis of knowing how each of these parts operates in relation to others. The concept of an open system also challenges all traditional views on causality, offering complex reciprocal determination instead of simple sequential or linear causality. Thus, G. has become a new perspective both for considering the behavior of various kinds of systems, and for understanding people as elements of open systems. See also Adaptation, General Adaptation Syndrome, General Systems, Lens Model, Soul-Body Relationship Question R. Enfield
HOMEOSTASIS
the general principle of self-regulation of living organisms, formulated by Cannon in 1926. Perls emphasizes the importance of this concept in his work "The Gestalt Approach and Eye Witness to Therapy", begun in 1950, completed in 1970 and published after his death in 1973.
homeostasis
The process by which the body maintains balance in its internal physiological environment. Through homeostatic impulses, the urge to eat, drink and regulate body temperature occurs. For example, a decrease in body temperature initiates many processes (such as shivering) that help restore normal temperature. Thus, homeostasis initiates other processes that act as regulators and restore the optimal state. As an analogue, you can bring a central heating system with thermostatic control. When the room temperature drops below the values set in the thermostat, it turns on the steam boiler, which pumps hot water into the heating system, raising the temperature. When the temperature in the room reaches a normal level, the thermostat turns off the steam boiler.
HOMEOSTASIS
homeostasis) - the physiological process of maintaining the constancy of the internal environment of the body (ed.), in which various parameters of the body (for example, blood pressure, body temperature, acid-base balance) are maintained in balance, despite changes in environmental conditions. - Homeostatic.
homeostasis
Word formation. Comes from the Greek. homoios - similar + stasis - immobility.
Specificity. The process by which a relative constancy of the internal environment of the body is achieved (constancy of body temperature, blood pressure, blood sugar concentration). As a separate mechanism, neuropsychic homeostasis can be distinguished, due to which the preservation and maintenance of optimal conditions for the functioning of the nervous system in the process of implementing various forms of activity is ensured.
HOMEOSTASIS
Literally translated from Greek means the same state. American physiologist W.B. Cannon introduced this term to refer to any process that changes an existing condition or set of circumstances and, as a result, initiates other processes that perform regulatory functions and restore the original state. The thermostat is a mechanical homeostat. This term is used in physiological psychology to refer to a number of complex biological mechanisms that operate through the autonomic nervous system, regulating factors such as body temperature, body fluids and their physical and chemical properties, blood pressure, water balance, metabolism, etc. For example, a decrease in body temperature initiates a number of processes, such as shivering, piloerection, and an increase in metabolism, which cause and maintain a high temperature until a normal temperature is reached.
HOMEOSTASIS
from the Greek homoios - similar + stasis - state, immobility) - a type of dynamic balance, characteristic of complex self-regulating systems and consisting in maintaining parameters essential for the system within acceptable limits. The term "G." proposed by the American physiologist W. Cannon in 1929 to describe the state of the human body, animals and plants. Then this concept became widespread in cybernetics, psychology, sociology, etc. The study of homeostatic processes involves the selection of: 1) parameters, significant changes in which disrupt the normal functioning of the system; 2) the limits of the permissible change of these parameters under the influence of the conditions of the external and internal environment; 3) a set of specific mechanisms that begin to function when the values of variables go beyond these boundaries (B. G. Yudin, 2001). Each conflict reaction of any of the parties in the event of the emergence and development of a conflict is nothing more than the desire to maintain its G. The parameter, the change of which triggers the conflict mechanism, is the damage predicted as a consequence of the actions of the opponent. The dynamics of the conflict and the pace of its escalation are regulated by feedback: the reaction of one side of the conflict to the actions of the other side. For the last 20 years Russia has been developing as a system with lost, blocked or extremely weakened feedback. Therefore, the behavior of the state and society in the conflicts of the given period, which destroyed the national economy of the country, is irrational. The application of G.'s theory to the analysis and regulation of social conflicts can significantly increase the effectiveness of the work of domestic conflictologists.
