i which are simultaneously joining in process of ventilation or escape from it. Liver acynuses, vascular segments of mesentery, pulmonary vascular functional units, etc., are the analogues of composite SFU. Thus, simple SFU is the object which can react to certain external influence, while the result of its performance would always be maximal because the control block would not control it, ie it works under the "all-or-none" law. The type of its reaction is caused by the type of SFU. There are two kinds of simple SFU: uncontrollable and controllable. Both react to the specific external influence. But additional external permission signal at the command entry point is required for the operation of controllable SFU, whereas the uncontrollable SFU have no command entry point. Therefore, the uncontrollable SFU does not depend on any external guiding signals. The control block of controllable and uncontrollable SFU consists of the analyzer-informant and has only DPC (the "Х" informant and afferent channels). The composite Systemic Functional Unit is a kind of an object similar to simple SFU, but the result of its action is stronger. It works under the "all-or-none" law, too, and its reaction is stipulated by type and number of its SFU. It can really be that the constituent parts of composite SFU may be controllable and uncontrollable, and the difference between them may only be stipulated by the presence of command entry point in the general control block through which the permission for the performance of action is communicated. The control block of a system is elementary, too, and has only DPC and analyzer-informant. Hence, any SFU function under the "all-or-none" law. SFU is arranged in such a way that it either does nothing, or gives out a maximal result of action. Its elementary result of action is either delivered or not delivered. There might be SFU which delivers the result of action, for example, twice as large as the result of action of another SFU. But it will always be twice as large. Each result of action of a simple SFU is quantum of action (indivisible portion), at that being maximal for the given SFU. It is indivisible because SFU cannot deliver part (for instance, half) of the result of action. And as far as it is "the indivisible portion" there can not be a gradation. For instance, SFU may be opened or closed, generate or not generate electric current, secrete or not secrete something, etc. But it cannot regulate the quantity of the result of action as its result always is either not delivered or is maximal. Such operating mode is very rough, inaccurate and unfavorable both for the SFU per se and its goal/objective. Let's imagine that instead of a steering wheel in our car there will be a device which will right away maximally swerve to the right when we turn a steering wheel to the right or will maximally swerve to the left if we turn it to the left. Instead of smooth and accurate trimming to follow the ...
