The reactivity of an organism is its property differentiated response to the influence of stimuli. It affects the ability of the animal or person to adapt to environmental conditions and maintain homeostasis. Let us further consider how reactivity of the body.

reactivity of the organism


Evaluation of the differential response is carried outby qualitative and quantitative indicators. Reactivity must be distinguished from the reaction. Under the latter, the correction of structure, function, and metabolic processes in response to the influence of stimuli is directly understood. The reactivity of the organism determines the characteristics of the response. At the same time, the initial state of the executive systems affects its level. The reactivity, therefore, depends on the reactivity.

Features of manifestation

There are the following forms of body reactivity:

  1. Normal is a norm.
  2. Increased hypergia. In this case, the excitation processes are predominant.
  3. Lowered - hypothermia. In this case, the processes of inhibition will be predominant.
  4. Perverted - dysergia.

That or other immunological reactivity of the organism can take place in every single system. In general, a person or an animal can manifest only one of them. In clinical practice, hypergic diseases are understood as pathologies with pronounced symptomatology, rapid flow, and under hypoergic diseases - sluggish diseases with an erased clinical picture. It must be taken into account that the answer to this or that stimulus may be different. For example, increased reactivity of the body may be noted for the allergen. At the same time, to another stimulus (temperature, for example) it can be low.

Valuation indicators

It must be said that only quantitativecharacteristics do not allow a complete picture of reactivity. In this connection, qualitative indicators are used. Among the basic quantities characterizing the forms reactivity of the organism, It should be noted:

  1. Irritability. It is a common property of the living to express elementary reactions.
  2. Excitability. It is the ability of the nervous, muscle and some other tissues to respond to the influence of stimuli and impart an impulse to other systems.
  3. Resistance. It is expressed in the resistance to the influence of extreme stimuli, the ability to resist without significant adjustments to the state of the internal environment.
  4. Functional mobility. It expresses this or that intensity of elementary reactions that accompany the physiological activity of a particular apparatus.
  5. Sensitivity. It is the ability to determine the localization, quality and strength of the stimulus, inform other systems about it.
    immunological reactivity of the organism


The following types of reactivity:

  1. Primary (species).
  2. Group (typical).
  3. Individual.

The last two, in turn, can be:

  1. Physiological.
  2. Pathological.

They are divided into specific and nonspecific. Consider these types of reactivity separately.

Primary Response

Reactivity of the body is based on biological abilityreact to the influence of adequate environmental stimuli. The primary response is a combination of protective adaptive mechanisms that are inherent in a particular animal. Reactivity of the body, in particular, is expressed in instincts, anabiosis,seasonal sleep, resistance to various influences. It has been established that turtles do not show sensitivity to tetanus toxin, rats do not develop anthrax, pathogenicity of the gonococcus manifests itself only in respect of the monkey and man. From the species reactivity depends on the ability of the species, its features and characteristics, which were formed during evolution and entrenched in the genotype.

Group and individual response

They are formed on the basis of primary reactivity (species). Individual response is due to acquired and hereditary traits. This reactivity of the organism depends on the sex, age, functionalthe state of systems, primarily the nervous and endocrine, the constitution, external stimuli. Group response is characteristic for associations of people similar in some hereditary-constitutional features. Physiological refers to the reactivity of a healthy, normal organism in a favorable environment of existence, adequately responding to the influence of stimuli. The pathological response appears under the influence of pathogens. It manifests itself in a decrease in the adaptive abilities of a recovering or ailing organism. Such a response may be a consequence of a violation of either the genetic program itself (hereditary diseases) or the mechanisms for its implementation (acquired pathologies).

forms of body reactivity

Specific answer

It is the ability of the bodyreact to antigenic irritation. With specific reactivity, humoral antibodies are produced, and a complex of specifically directed cellular reactions is activated. Such a response provides resistance to infections, adaptation to certain environmental conditions (for example, to lack of oxygen). Pathological specific reactivity occurs in immunopathological processes. It can be different allergies, autoimmune diseases and conditions. It is expressed by specific reactions, through which a pattern of pathology of a specific nosological form is formed. For example, with infections, there is a rash, with hypertension arteries are in a spastic state, with radiation sickness the hemopoietic system is affected and so on.

Nonspecific reaction

It is the ability to exercisethe same type of response to various stimuli. Such reactivity is manifested as an adaptation to several external factors. For example, at the same time to lack of oxygen and physical activity. It is expressed as a stress-reactivity and resistance of the body. The latter is a resistance to damage. Here it should be noted one nuance. Nonspecific resistance of the body is not specific to any agent ortheir group. The answer and stability are expressed in relation to the damage in general of various stimuli, including extreme ones. Pathological nonspecific reactivity is manifested by reactions characteristic of many diseases (typical form of neurogenic dystrophy, parabiosis, pain, fever, response to anesthesia, shock and so on).

Reactivity and resistance of the body

These two manifestations are closely related to each other. Reactivity is a broader concept and includes resistance. It expresses the mechanisms of the latter, the relation of systems to any agent. Resistance reflects the processes of reactivity as protective-adaptive. It expresses the relation only to the extreme irritant. It should be said that changes in the reactivity of the organism and its stability does not always occurSimultaneously. For example, with anaphylaxis, the first increases, but the resistance decreases. At winter hibernation, on the contrary, the reactivity decreases, but the resistance to some stimuli increases. In this regard, the tactics of the doctor in the treatment of pathologies should be selected strictly individually. With chronic, sluggish diseases, violations of internal organs, injuries, an increase in the reactivity of the body will give a positive effect. In this case, treatment of allergies should be accompanied by a decrease in its level relative to a specific stimulus.

changes in the reactivity of the organism


Factors determining the reactivity of the body and its stability, are formed on the basis of itsconstitution, heredity, the specifics of metabolic processes, the state of the endocrine, nervous and other systems. They depend on sex, age, external stimuli. Factors of organism reactivity Are genetically determined elementarysigns. They are manifested in the phenotype. Reactivity can be considered as a combination of these features, functionally stable combinations created by the integrative apparatus.

Specificity of formation

Reactivity is created at all levelsorganization. For example, at the molecular level it is a manifestation of a reaction to hypoxia accompanying sickle cell anemia, on the cellular one - with phagocytosis, etc. All mechanisms are strictly individual. At the organism and system levels, a qualitatively new integration is formed, conditioned by the tasks of the concrete system. The leading role in this case belongs to the nervous system. In higher animals, it forms the response at all sites - at the level of receptors, in conductors, in the oblong and spinal cord, in the cortex and subcortical region, and in humans - within the second signal system and largely depends on social conditions. In this connection, changes in the functional state of the central nervous system provoke the corresponding reactivity processes. This is reflected in the response to various effects, resistance to negative agents. For example, due to decortication, resistance to oxygen starvation is enhanced. If the gray hillock is damaged, the resistance to infection decreases.

Endocrine system

It is of no small importance in the process offormation of resistance and reactivity. Special functions are performed by hormones in the anterior pituitary, brain and cortex of the adrenal gland. So, due to adrenalectomy, the resistance to mechanical injuries, the impact of electric current, bacterial toxins is sharply reduced. With the introduction of glucocorticoids in the optimal dosage, the resistance to extreme irritants is enhanced. The immune system and connective tissue cause nonspecific and specific reactions - the production of antibodies by plasma cells, phagocytosis of microphages.

pathology of body reactivity

Biological barriers

They provide nonspecific resistance. There are barriers:

  1. External. These include skin, mucous membranes, digestive apparatus, respiratory organs, etc.
  2. Internal - histogematic (hemato-ophthalmic, hematoencephalic, hematolabyrinth and others).

These biological barriers, as well as activethe compounds present in body fluids perform regulatory and protective functions. They support the optimal nutrient medium for the organ, contribute to the maintenance of homeostasis.


Reactivity and resistance of the organism -the results of a long evolutionary development. Unicellular organisms exhibit quite pronounced resistance to hyper- and hypothermia, hypoxia, ionizing radiation and other effects. However, their reactivity is rather limited. Invertebrates and protozoa, these abilities are manifested at the cellular level. Resistance and reactivity are limited by the different course of metabolic processes. Thus, their inhibition can tolerate a decrease in temperature, drying out, a decrease in the oxygen content, etc. Animals possessing a primitive CNS express resistance and reactivity through neutralization of poisons, mobilization of additional energy sources. In the process of the formation of the nervous system, in the course of evolution, there arose more and more possibilities for an active reaction to stimuli due to protective adaptive mechanisms. Due to the response to damage, the vital activity of the organism changes. This ensures the existence of a new environment. This is the role of the reactivity of the organism.

factors of the organism's reactivity


In the early stages of development, resistance andreactivity are manifested at the molecular level. In the next stage of ontogeny, the response occurs in cells. In particular, an abnormal development that leads to ugliness begins. In the early stages, the body is less resistant to long-term adverse effects. Together with this, he shows a high resistance to short-term irritants. For example, in early childhood, mammals are more tolerant of acute oxygen starvation. This is due to the fact that at this stage of ontogeny, the intensity of oxidation processes is rather low. Accordingly, the need for oxygen is not so high. In addition, resistance to a number of toxins is observed. This is due to the fact that in the body there are still no reactive structures responsible for the perception of the action of stimuli. At the same time, in the early stages, the protective barriers and adaptations are not sufficiently differentiated and developed. Reduced sensitivity of newborns to oxygen starvation and toxins can not make up for the lack of active mechanisms. In this regard, the course of infections in them is quite difficult. This is mainly due to the fact that the child is born with an underdeveloped nervous system in a morphological and functional sense. In the course of ontogenesis, a gradual complication of reactivity occurs. It becomes more diverse, perfect due to the formation of the nervous system, the improvement of metabolic processes, the establishment of correlative interactions between intrasecretary glands. As a result, the picture of the disease becomes more complicated. At the same time, defense mechanisms, barrier systems, the ability to produce antibodies are actively developing (for example, inflammation occurs). Both the reactivity of the organism and its resistance to irritants pass through several stages in its development. The first is in the early childhood. In this period, the reactivity and resistance are reduced. In adulthood, they intensify. At the onset of old age they again decrease.

Methods of strengthening

Any impact that contributes to changefunctional state of regulatory or executive systems, affects reactivity and resistance. Negative effect has mental trauma, negative emotions, physical overwork, malnutrition, chronic alcoholism, beriberi, etc. As a result, the pathology of the reactivity of the organism arises. Strengthening the ability to withstand the impact of certain stimuli can be achieved by reducing the activity of life. In particular, we are talking about anesthesia, hypothermia, hibernation. In the latter case, if the animal is infected with tuberculosis, the plague, the disease will not develop (they will appear on awakening). In a state of hibernation, resistance to hypoxia, radiation exposure, poisoning, and infections is increased. Anesthesia provides an increase in resistance to electric current. In such a state, streptococcal sepsis does not develop. The second group of methods are methods of increasing stability while maintaining or activating vital activity. They include:

  1. Training of key functional systems. For example, it can be hardening.
  2. Change in the functions of regulatory systems. In particular, autogenic training, verbal suggestion, hypnosis, acupuncture and so on are used.
  3. Nonspecific therapy. It includes balneotherapy, the use of pharmacological agents.
    reactivity of the organism pathophysiology


The doctrine of them is associated with the name of Lazarev. It was he who laid the foundations of the "pharmacology of health". Adaptogens are agents that accelerate the adaptation of the body to adverse effects. They ensure the normalization of disturbances, provoked by stresses. Adaptogens have a wide therapeutic effect, increase resistance against a variety of physical, chemical, biological agents. The mechanism of their action is based on stimulating the synthesis of protein and nucleic acids, stabilizing biological membranes. Using adaptogens, as well as a number of other drugs, adapting the body to the effects of unfavorable external factors, it is possible to form a state of unspecific high resistance. A key condition in its development is a dosed increase in the intensity of the negative influence. Management of resistance and reactivity is a promising area of ​​curative and preventive medicine.

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