Radioactivity and life. YK Kudrytski (MD) 1971 Part 14.

radiation for a long time remained controversial. It is important to clearly distinguish between two notions: threshold effects of radiation and radiation reaction threshold. It is considered, as discussed in the first section of the brochure that the effect of radiation doorsteps. To understand the patterns of the same biological effects of ionizing radiation are important knowledge about the threshold of radiation reactions.
A threshold of radiation reaction - one of the main body of radiobiological response patterns to radiative forcing. It is one of the most important radiobiological basis of radiation hygiene. Without her knowledge can not be addressed such issues as the rationale for maximum permissible levels of ionizing radiation.
Due to the controversial questions is useful to begin with a definition. Below the threshold of response or reaction, refers to qualitative change in response of an organism in response to changes in the magnitude and spatial and temporal characteristics of stimuli.
Thus, the threshold for the reaction is a manifestation of the transition of the body and its functions from one qualitative state to another as a result of gradual quantitative change in subthreshold reactions took effect on increasing the stimulus. Emergence as a new qualitative state, as Engels noted, is one of the main prienakov development process.
As follows from the definition of a threshold in the response of organisms characteristic of any stimulus. An example is a typical process as blood loss. Indeed, it may be so small that no alteration in blood pressure, one of the vital signs, changing under the influence of blood loss. Consequently, the physiological regulation of blood pressure can compensate for the loss of 10-14% of blood without disruption of its level.
If you lose the same 25-30% of all blood arterial pressure decreases, but after a while due to the inclusion of protective compensatory mechanisms independently restored. Consequently, when such compensation is achieved krovopo tere is a qualitatively different way.
Finally, the loss of 50-60% of blood process becomes irreversible, or, as doctors say, dekompeyasirovannym. Thus, depending on the magnitude of blood loss there are three qualitatively different forms of reaction mechanisms that regulate blood pressure. In this negrudno indicate at what value there is a new form of bleeding response, which must be taken to its threshold.
It is interesting to note the analogy with the beam factor for besporogonosti action: for how small the least blood loss, it is always a decrease in blood volume, as well as potloschenie photon ionizing radiation is always associated with the possibility of violations of the chemical bond.
On the example of blood loss can be demonstrated aavisimosg. 01 'distribution in time. It is well known that slow blood letting a certain amount of blood pressure can not be changed. whereas a rapid loss of the same volume of blood will be accompanied by a pronounced fall in blood pressure. It also negrudno