The reactivity of an organism is its property to respond differently to the influence of stimuli. The ability of an animal or a person to adapt to environmental conditions and maintain homeostasis depends on it. Consider further how the reactivity of the body manifests itself.
Pathophysiology
Evaluation of a differentiated response is carried out according to qualitative and quantitative indicators. Reactivity must be distinguished from reaction. The latter is understood as a direct correction of the structure, function, metabolic processes in response to the influence of stimuli. 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. Reactivity thus determines the magnitude of the reaction.
Features of manifestation
There are the following forms of organism reactivity:
- Normal - normergy.
- Increased - hypergia. In this case, excitation processes are predominant.
- Reduced - hypoergy. In this caseinhibition processes will prevail.
- Perverted - dysergia.
This or that immunological reactivity of an organism can take place in each separate system. In general, a person or an animal can manifest only one of them. In clinical practice, hyperergic diseases are pathologies with pronounced symptoms, a rapid course, and hypoergic diseases are 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 observed in relation to the allergen. However, to another stimulus (temperature, for example), it can be low.
Evaluation indicators
It must be said that only quantitative characteristics do not allow a complete picture of the reactivity. In this regard, qualitative indicators are used. Among the main values characterizing the forms of reactivity of the organism, it should be noted:
- Irritability. It represents the general property of the living to express elementary reactions.
- Excitability. It represents the ability of nervous, muscular and some other tissues to respond to the influence of stimuli and transmit impulses 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 this or that intensity of elementary reactions that accompanyphysiological 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 body reactivity 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 body reactivity separately.
Primary response
The reactivity of the body is based on the biological ability to respond to the influence of adequate environmental stimuli. The primary response is a set of protective and adaptive mechanisms that are inherent in specific animals. The reactivity of the organism, in particular, is expressed in instincts, suspended animation, seasonal sleep, and resistance to various influences. It has been established that turtles are not sensitive to tetanus toxin, rats are not vaccinated with anthrax, the pathogenicity of gonococcus is manifested only in relation to monkeys and humans. Species reactivity determines the abilities of the species, its features and characteristics, which were formed in the course of evolution and were fixed in the genotype.
Group and individual response
They are formed on the basis of primary reactivity (species). The individual response is dueacquired and hereditary traits. This reactivity of the organism depends on gender, age, functional state of systems, primarily nervous and endocrine, constitution, external stimuli. A group response is characteristic of associations of people who are similar in some hereditary constitutional features. Physiological is called the reactivity of a he althy, normal organism in a favorable environment of existence, adequately responding to the influence of stimuli. Pathological response appears under the influence of pathogenic agents. It manifests itself in a decrease in the adaptive abilities of a recovering or ill organism. Such a response may be the result of a violation of either the genetic program itself (hereditary diseases), or the mechanisms for its implementation (acquired pathologies).
Specific response
It represents the body's ability to respond to antigenic irritation. With specific reactivity, humoral antibodies are produced, a complex of specifically directed cellular reactions is activated. Such a response provides resistance to infections, adaptation to certain environmental conditions (for example, to a 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 picture of the pathology of a particular nosological form is formed. For example, with infections, a rash occurs, withhypertension, the arteries are in a spastic state, radiation sickness affects the hematopoietic system, and so on.
Non-specific reaction
It represents the ability to show the same type of response to various stimuli. This reactivity appears as an adaptation to several external factors. For example, at the same time to a lack of oxygen and physical activity. It is expressed as stress reactivity and resistance of the body. The latter is damage resistance. One nuance should be noted here. Nonspecific resistance of the organism does not manifest itself specifically to any agent or group of agents. The response and stability are expressed in relation to the 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 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 and adaptive. It expresses the attitude only to the extreme irritant. It should be said that changes in the reactivity of the organism and its stability do not always occur simultaneously. For example, with anaphylaxis, the first increases, but resistance decreases. During winter hibernationon the contrary, reactivity decreases, but resistance to certain stimuli increases. In this regard, the doctor's tactics 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 have a positive effect. In this case, the treatment of allergies should be accompanied by a decrease in its level relative to a specific irritant.
Mechanisms
The factors that determine the reactivity of the organism and its stability are formed on the basis of its constitution, heredity, the specifics of metabolic processes, the state of the endocrine, nervous and other systems. They depend on gender, age, external stimuli. The reactivity factors of an organism are genetically determined elementary signs. They show up in the phenotype. Reactivity can be considered as a combination of these features, functionally stable combinations created by the integrative apparatus.
Specific formation
Reactivity is created at all levels of the organization. For example, on the molecular level, this is a manifestation of a reaction to hypoxia that accompanies sickle cell anemia, on the cellular level, during phagocytosis, etc. All mechanisms are strictly individual. At the organismic and system levels, a qualitatively new integration is 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 level of receptors, in conductors, inmedulla oblongata and spinal cord, in the cortex and subcortical region, and in humans - within the second signaling system and largely depends on social conditions. In this regard, changes in the functional state of the CNS provoke the corresponding processes of reactivity. This is reflected in the response to various influences, resistance to negative agents. For example, as a result of decortication, resistance to oxygen starvation increases. When the gray tubercle is damaged, resistance to infections decreases.
Endocrine system
It is of no small importance in the process of formation of resistance and reactivity. Special functions are performed by hormones in the anterior lobe of the pituitary gland, the medulla and cortical substance of the adrenal glands. So, as a result of adrenalectomy, resistance to mechanical injuries, the effects of electric current, and bacterial toxins is sharply reduced. With the introduction of glucocorticoids in the optimal dosage, resistance to extreme stimuli 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 the skin, mucous membranes, digestive apparatus, respiratory organs, etc.
- Internal - histohematic (hematoophthalmic, hematoencephalic, hematolabyrinth and others).
These biological barriers, as well as activecompounds present in body fluids perform regulatory and protective functions. They maintain an optimal nutritional environment for the organ, help to ensure homeostasis.
Phylogenesis
Reactivity and resistance of an organism are the results of a long evolutionary development. Unicellular organisms show a fairly pronounced resistance to hyper- and hypothermia, hypoxia, ionizing radiation and other influences. However, 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. Thus, their inhibition makes it possible to tolerate a decrease in temperature, desiccation, a decrease in oxygen content, etc. Animals with a primitive central nervous system express resistance and reactivity through poison neutralization reactions, mobilization of additional energy sources. In the process of the 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. Due to the response to damage, the vital activity of the organism changes. Due to this, existence in a new environment is ensured. This is the role of the reactivity of the organism.
Ontogeny
In the early stages of development, resistance and reactivity appear at the molecular level. At the next stage of ontogeny, the response occurs in the cells. In particular, abnormal development begins, which leads todeformities. In the early stages, the body is less resistant to long-term negative effects. At the same time, it exhibits high resistance to short-term stimuli. For example, mammals in early childhood tolerate acute oxygen starvation more easily. 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, there is resistance to a number of toxins. This is due to the fact that the body still lacks reactive structures responsible for the perception of the action of stimuli. At the same time, in the early stages, protective barriers and adaptations are not sufficiently differentiated and developed. Reduced sensitivity of newborns to oxygen starvation and toxins cannot compensate for the lack of active mechanisms. In this regard, the course of infections they have is quite severe. This is mainly due to the fact that the child is born with an underdeveloped nervous system in morphological and functional terms. 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 the intrasecretory glands. As a result, the picture of the disease becomes more complicated. At the same time, defense mechanisms, barrier systems, and the ability to produce antibodies are actively developing (for example, inflammation occurs). Both the reactivity of the organism and its resistance to stimuli pass several stages in their development.stages. The first is in early childhood. In this period, reactivity and resistance are lowered. In adulthood, they intensify. With the onset of old age, they decrease again.
Strengthening Methods
Any impact that contributes to a change in the functional state of regulatory or executive systems affects reactivity and resistance. Mental trauma, negative emotions, physical overwork, malnutrition, chronic alcoholism, beriberi, etc. have a negative effect. As a result, a pathology of the body's reactivity occurs. Strengthening the ability to endure the impact 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 a state of hibernation, resistance to hypoxia, radiation exposure, poisoning, and infections increases. Anesthesia provides an increase in resistance to electric current. In this state, streptococcal sepsis does not develop. The second group of methods consists of techniques for increasing stability while maintaining or enhancing vital activity. These include:
- Training of key functional systems. For example, it could be hardening.
- Changing the functions of regulatory systems. In particular, autogenic training, verbal suggestion, hypnosis, acupuncture and so on are used.
- Non-specific therapy. It includes balneotherapy,the use of pharmacological agents.
Adaptogens
The teaching about them is associated with the name of Lazarev. It was he who laid the foundations of "he alth pharmacology". Adaptogens are agents that accelerate the body's adaptation to adverse effects. They provide normalization of disturbances provoked by stress. Adaptogens have a wide therapeutic effect, enhance resistance to a number of physical, chemical, biological agents. The mechanism of their action is based on stimulation of protein and nucleic acid synthesis, stabilization of biological membranes. Using adaptogens, as well as a number of other drugs, by adapting the body to the effects of adverse external factors, it is possible to form a state of nonspecific high resistance. The key condition for its development is a dosed increase in the intensity of negative influence. Management of resistance and reactivity is a promising direction in therapeutic and preventive medicine.
