rbation action/disturbing influences. Hence, one can see that it is NF that turns SFU into real systems. How does the control block manage the system? What parameters are characteristic of it? Any control block is characterized by three DPC parameters and the same number of NF loop parameters. For DPC it is a minimal level of controllable input stimulus (threshold of sensitivity); maximal level of controllable input stimulus (range of input stimulus sensitivity); time of engagement of control (decision-making time). For NF loop it is minimal level of controllable result of action (threshold of sensitivity of NF loop - NF profundity/intensity); maximal level of controllable result of action (Range of sensitivity of the result of action); time of engagement of control (decision-making time). Minimal level of controllable input signal for DPC is the sensitivity threshold of signal of the "Х" receptor wherefrom the analyzer-informant recognizes that the external influence has already begun. For example, if рО2 has reached 60 mm Hg the sphincter should be opened (1 SFU is actuated), if the рО2 value is smaller, then it is closed. Any values ​​of рО2 smaller than 60 mm Hg would not lead to the opening of sphincter, because these are sub-threshold values. Consequently, 60 mm Hg is the operational threshold of sphincter. Maximum level of controllable entrance signal (range) for DPC is the level of signal about external influence at which all SFU are actuated. The system cannot react to the further increase in the input signal by the extension of its function, as it does not have any more of SFU reserves. For example, if рО2 has reached 100 mm Hg all sphincters should be opened (all SFU are activated). Any values ​​of рО2 larger than 100 mm Hg will not lead to the opening of additional sphincters, because all of them are already opened, i.e. the values ​​of 60-100 mm Hg are the range of activation of the system of sphincters. Time of DPC activation is a time interval between the onset of external influence and the beginning of the system's operation. The system would never respond immediately after the onset of external influence. Receptors need to feel a signal, the analyzer-informant needs to make the decision, the effectors transfer the guiding impact to the command entry points of the executive elements - all this takes time. The minimal level of the controllable exit signal for NF is a threshold of sensitivity of a signal of the "Y" receptor, wherefrom the analyzer-informant recognizes whether there is a discrepancy between the result of action of the system and its due value. The discrepancy should be equal to or more than the quantum of action of single SFU. For example, if one sphincter is to be opened and the bloodstream should be minimal (one quantum of action), whereas two sphincters are actually opened and the bloodstream is twice as intensive (two quanta of action), the "Y" receptor should feel an extra qua...
