The reactivity of an organism is its ability to respond differentially to the influence of stimuli. The ability of an animal or a person to adapt to environmental conditions and maintain homeostasis depends on it. Let us further consider how the reactivity of the organism is manifested .
Pathophysiology
Differentiated response is assessed by qualitative and quantitative indicators. Reactivity must be distinguished from reaction. By the latter is understood directly the correction of the structure, function, metabolic processes in response to the influence of stimuli. The reactivity of the body determines the characteristics of the response. At the same time, the initial state of executive systems influences its level. Thus, the magnitude of the reaction depends on the reactivity.
Features of manifestation
The following forms of body reactivity are :
- Normal is normergia.
- Increased - hypergia. In this case, excitation processes are predominant.
- Lowered - hypoergy. In this case, the braking processes will prevail.
- Perverted - dysergy.
This or that immunological reactivity of an organism can take place in each separate system. In general, a person or animal can exhibit only any one of them. In clinical practice, hypergical diseases are understood as pathologies with pronounced symptoms, rapid course, and hypoergic diseases are understood as sluggish diseases with an erased clinical picture. It should be noted that the response to a particular stimulus may be different. For example, an increase in the reactivity of the body can be noted in relation to the allergen. However, to another stimulus (temperature, for example), it can be low.
Assessment indicators
It must be said that only quantitative characteristics do not allow a complete picture of reactivity. In this regard, quality indicators are used. Among the main quantities characterizing the forms of reactivity of the body, it should be noted:
- Irritability. It represents the general property of the living to express elementary reactions.
- Excitability. It represents the ability of nerve, muscle and some other tissues to respond to the influence of stimuli and transmit momentum to other systems.
- Resistance It is expressed in resistance to the influence of extreme stimuli, the ability to resist without significant adjustments to the state of the internal environment.
- Functional mobility. It expresses one or another intensity of elementary reactions that accompany the physiological activity of a particular apparatus.
- Sensitivity. It represents the ability to determine the localization, quality and strength of the stimulus, to inform other systems about it.
Classification
The following types of reactivity of the body are distinguished:
- Primary (species).
- Group (typical).
- Individual.
The last two, in turn, can be:
- Physiological.
- Pathological.
They are divided into specific and non-specific. Consider these types of reactivity of the body separately.
Primary answer
The body's reactivity is based on the biological ability to respond to the effects of adequate environmental stimuli. The primary response is a combination of protective and adaptive mechanisms that are inherent in specific animals. The reactivity of an organism , in particular, is expressed in instincts, suspended animation, seasonal sleep, resistance to various influences. It was found that turtles do not show sensitivity to tetanus toxin, anthrax is not vaccinated in rats, the pathogenicity of gonococcus is manifested only in relation to monkeys and humans. The species’s abilities, its features and characteristics that formed during evolution and are fixed in the genotype depend on species reactivity.
Group and individual response
They are formed on the basis of primary reactivity (species). An individual response is due to acquired and hereditary traits. This reactivity of an organism depends on gender, age, functional state of systems, primarily nervous and endocrine, constitution, and external stimuli. A group response is characteristic of associations of people who are similar in some hereditary-constitutional terms. Physiological refers to the reactivity of a healthy, normal organism in a favorable environment of existence that adequately responds to the influence of stimuli. The pathological response appears under the influence of pathogenic agents. It manifests itself in a decrease in the adaptive abilities of a recovering or sick body. Such an answer may be the result of a violation of either the genetic program itself (hereditary diseases) or the mechanisms of its implementation (acquired pathologies).
Specific answer
It represents the body's ability to respond to antigenic irritation. With specific reactivity, humoral antibodies are produced, a complex of specifically targeted cellular reactions is activated. This response provides resistance to infections, adaptation to certain environmental conditions (for example, to a lack of oxygen). Pathological specific reactivity occurs in immunopathological processes. These can be different allergies, autoimmune diseases and conditions. It is expressed by specific reactions by which a pathology picture of a particular nosological form is formed. For example, with infections, a rash occurs, with hypertension, the arteries are in a spastic state, with radiation sickness the blood-forming system is affected, and so on.
Nonspecific reaction
It represents the ability to exhibit a uniform response to various stimuli. Such reactivity manifests itself as an adaptation to several external factors. For example, at the same time to lack of oxygen and physical activity. It is expressed as stress reactivity and body resistance . The latter is damage resistance. One nuance should be noted here. Nonspecific resistance of the organism does not appear specifically to any agent or their group. The response and stability are expressed with respect to damage in general to various stimuli, including extreme ones. Pathological nonspecific reactivity is manifested by reactions characteristic of many diseases (a typical form of neurogenic dystrophy, parabiosis, pain, fever, response to anesthesia, shock, and so on).
Reactivity and body resistance
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 attitude of systems to any agent. Resistance reflects reactivity processes as protective and adaptive. She expresses attitude only to an extreme irritant. It should be said that changes in the reactivity of an organism and its stability do not always occur simultaneously. For example, with anaphylaxis, the first increases, but resistance decreases. With hibernation, on the contrary, reactivity decreases, but at the same time, resistance to some irritants increases. In this regard, the tactics of the doctor in the treatment of pathologies should be chosen strictly individually. In chronic, sluggish diseases, disorders of the internal organs, injuries, an increase in the reactivity of the body will give a positive effect. In this case, the treatment of allergies should be accompanied by a decrease in its level relative to a specific irritant.
The mechanisms
Factors that determine the reactivity of an organism and its stability are formed on the basis of its constitution, heredity, specificity of metabolic processes, the state of endocrine, nervous and other systems. They depend on gender, age, external stimuli. The reactivity factors of an organism are genetically determined elementary traits. They appear in the phenotype. Reactivity can be considered as a combination of these features, functionally stable combinations created by the integrative apparatus.
The specifics of the formation
Reactivity is created at all levels of the organization. For example, on the molecular - this is a manifestation of the reaction to hypoxia that accompanies sickle-cell anemia, on the cellular - with phagocytosis, etc. All mechanisms are strictly individual. At the organismic and systemic levels, a qualitatively new integration is being formed, determined by the tasks of a particular system. The leading role in this belongs to the nervous system. In higher animals, it forms a response in all areas - at the receptor level, in the conductors, in the medulla oblongata and spinal cord, in the cortex and subcortical region, and in humans - within the framework of the second signaling system and is largely dependent on social conditions. In this regard, 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 mound is damaged, resistance to infection decreases.
Endocrine system
It is of no small importance in the process of formation of resistance and reactivity. Hormones perform special functions in the anterior lobe of the pituitary, adrenal medulla and cortex. So, as a result of adrenalectomy, the resistance to mechanical injuries, the effects of electric current, and bacterial toxins sharply decreases. With the introduction of glucocorticoids in the optimal dosage, resistance to extreme irritants is enhanced. The immune system and connective tissue cause non-specific and specific reactions - the production of antibodies by plasma cells, phagocytosis of microphages.
Biological barriers
They provide non-specific resistance. There are barriers:
- External These include skin, mucous membranes, digestive apparatus, respiratory organs, etc.
- Internal - histohematic (blood-ophthalmic, blood-brain, blood-labyrinth and others).
These biological barriers, as well as the active compounds present in body fluids, perform regulatory and protective functions. They maintain an optimal nutrient medium for the organ, contribute to the provision of homeostasis.
Phylogenesis
The reactivity and resistance of the body are the results of a long evolutionary development. Unicellular show a fairly pronounced resistance to hyper- and hypothermia, hypoxia, ionizing radiation and other influences. Moreover, their reactivity is quite limited. In invertebrates and protozoa, these abilities are manifested at the cellular level. Resistance and reactivity are limited by the different course of metabolic processes. So, their inhibition allows you to tolerate a decrease in temperature, drying, a decrease in oxygen content, etc. Animals with a primitive central nervous system express resistance and reactivity through neutralization reactions of poisons, mobilization of additional energy sources. In the process of formation of the nervous system in the course of evolution, more and more opportunities arose for an active reaction to stimuli due to protective and adaptive mechanisms. Thanks to the response to damage, the vital activity of the body changes. Due to this, existence in a new environment is ensured. This is the role of the reactivity of the body.
Ontogenesis
In the early stages of development, resistance and reactivity manifest themselves at the molecular level. At the next stage of ontogenesis, the response occurs in cells. In particular, abnormal development begins, which leads to deformities. In the early stages, the body is less resistant to long-term negative effects. Along with this, he exhibits high resistance to short-term irritants. For example, mammals in early childhood more easily tolerate acute oxygen starvation. This is due to the fact that at this stage of ontogenesis, the intensity of oxidation processes is quite 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. However, in the early stages, protective barriers and devices are not sufficiently differentiated and developed. The reduced sensitivity of newborns to oxygen starvation and toxins cannot make up for the lack of active mechanisms. In this regard, the course of infections in them is quite severe. This is mainly due to the fact that the child is born with an underdeveloped morphological and functional nervous system. 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 intracretory glands. As a result, the picture of the disease is complicated. Along with this, defense mechanisms, barrier systems, and the ability to generate antibodies are actively developing (for example, inflammation occurs). Both the reactivity of an organism and its resistance to irritants go through several stages in their development. The first is in early childhood. In this period, reactivity and resistance are reduced. In adulthood, they increase. With the onset of old age, they again decline.
Reinforcement methods
Any effect that contributes to a change in the functional state of regulatory or executive systems affects reactivity and resistance. Mental trauma, negative emotions, physical fatigue, malnutrition, chronic alcoholism, vitamin deficiency, etc. have a negative effect. As a result, a pathology of the body's reactivity arises. Strengthening the ability to tolerate the effects of certain stimuli can be carried out by reducing the activity of life. In particular, we are talking about anesthesia, hypothermia, hibernation. In the latter case, when an animal is infected with tuberculosis, plague, diseases will not develop (they will appear upon awakening). In hibernation, resistance to hypoxia, radiation exposure, poisoning, infections increases. Anesthesia provides increased resistance to electric current. In this condition, streptococcal sepsis does not develop. The second group of methods consists of methods for increasing stability while maintaining or activating vital functions. These include:
- Training key functional systems. For example, it can be hardening.
- Changing the functions of regulatory systems. In particular, autogenic training, verbal suggestion, hypnosis, acupuncture, and so on are used.
- Nonspecific therapy. It includes balneotherapy, the use of pharmacological agents.
Adaptogens
The doctrine of them is connected with the name of Lazarev. It was he who laid the foundations of the "pharmacology of health." Adaptogens are agents that accelerate the body's adaptation to adverse effects. They provide the normalization of disorders caused by stress. Adaptogens have a wide therapeutic effect, increase resistance to a number of physical, chemical, biological agents. The mechanism of their action is based on the stimulation of protein and nucleic acid synthesis, stabilization of biological membranes. Using adaptogens, as well as a number of other drugs, adapting the body to the effects of adverse external factors, it is possible to form a state of non-specific high resistance. The key condition for its development is a metered increase in the intensity of the negative impact. Management of resistance and reactivity is a promising area of medical and preventive medicine.