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Forms and rates of reactivity

Reactivity and its role in the pathology

The definition of the term

Reactivity (from Lat. Reactio - opposition) is the property (ability) of the whole organism to respond differentially to the stimuli by changing of the vital activity. Reactivity makes thin differentiated body's response to the stimuli effects, determines the quantitative and qualitative features of the response reaction. The ability of a person (or animal) to adapt to their environment, to maintain homeostasis depends on reactivity to a large extent.

Reactivity should be distinguished from the reaction. Reaction is a change of exchange, structure and function in response to stimulation of the biological system, the expression of reactivity, but not the property of this organism. In other words, the reactivity is the essence, and the reaction is a phenomenon that reflects the nature of the biological system. Reactivity determines the characteristics of the reaction to certain effects. At the same time, the initial state of the executive systems that provides feedback can also influence on the level of reactivity, it means that reactivity directly determines the size of the reaction, but the reaction affects the level of reactivity too.

Forms and rates of reactivity

There are distinguished normal reactivity (normergy) increased (with a predominance of excitation) - hyperergy, reduced (with a predominance of inhibitory processes) - hypoergy and perverted (dizergy).

In its pure kind, these forms can be expressed with respect to individual organs and systems. In the whole body there may be the prevalence of one form only. In clinical practice the diseases with rapid flow, with strong symptoms are called hyperergic ones and the low current diseases with the erased symptoms are called hypoergic ones. Keep in mind that the reactivity can vary with respect to various environmental factors. For example, it can be a high reactivity of the organism to some allergen, but low for other stimulus (temperature factor).

However, the quantitative characterization of reactivity without qualitative indicators are insufficient for its full characterization.

The main quality parameters of reactivity are:

• Resistance (from Lat. Resistere – to resist) – organism’s stability to the action of pathogenic factors, the ability to resist without significant changes of the internal environment, the most important quality indicator of excellence of the reactivity;

• Irritability - common property of all living creatures that determines elementary reactions;

• functional mobility (lability) - "more or less rate of elementary reactions, which accompanies physiological activity of the unit" (N.E. Vvedensky);

• excitability - a property of certain tissues (nerve and muscle) to respond to stimulation of the excitation and transfer it to other tissues and organs;

• chronaxie - the least time of the stimulus of twice the threshold strength, sufficient to invoke physiological effect:

• Sensitivity - Property (ability) of the whole organism to determine the location, strength and quality of the acting stimulus and report it to the appropriate units of the body.


Date: 2015-01-11; view: 850


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