From Big Medical Encyclopedia

SYSTEM — the arranged complete set of the interconnected elements possessing own organization and structure.

The concept «system» is one of key in modern scientific knowledge, it is widely used at a research of natural phenomena and societies, and systems approach, i.e. representation in the form of S. of various difficult objects (biological, psychological, social etc.), opens new opportunities for their in-depth study. When complete natural or artificial objects for their studying present sets of the interconnected or interacting parts or elements in the form, speak about systems analysis of these objects (see. Systems analysis ); at association of any earlier separated objects or the phenomena (and also knowledge of them) on the basis of certain rules or patterns speak about systematization (see. Classification , Systematics ).

Distinguish two main types C. — material (natural inorganic, technical, biological, social) and abstract, being a product of activity of human consciousness (different theories, representation, etc.).

The main property C. as uniform set of the interacting elements is the integrity which is expressed in not reducibility of properties C. to the sum of properties of the parts making it. Set of elements C. and bonds between them represents structure of Page.

If S.'s condition and its elements changes in time, then S. is called dynamic, otherwise S. is static (static).

Many material S. (technical, economic, biological) function, i.e. in them there are changes and the operations leading to obtaining nek-ry results and achievement of definite purposes are performed. All functioning S. are in interaction with the environment. If between S. and Wednesday exchange only is carried out by energy, S. is called closed. If, besides, there is an exchange and substance, and energy, then such S. call open (see. Thermodynamics ).

In open S. in the stationary mode so-called labile equilibrium is maintained, at Krom all external characteristics and S.'s condition in general in time do not change, but there is a continuous balanced metabolism and energy to the environment.

Due to the development cybernetics (see), its methods and approaches much attention began to be paid to information exchange between this or that S. and Wednesday (in particular, at difficult social, biological, economic and technical S.' studying).

Problems of the description and S.'s studying are developed both from all-methodological positions, and from positions of various theoretical and applied sciences — theories of systems, theories of management (see. Management ), cybernetics (see), system engineerings (see) etc.; much attention in the modern theory of management is paid to researches various difficult, including and hierarchical, systems (big systems).

In medicine and biology simpler understanding of the term «system» is applied, as a rule, on the basis of what blood circulations etc. (allocate immune S., respiratory S., S. see. Biological system ). In physiology idea of so-called functional S. is widely used (see. Functional systems ). Methods of mathematical are applied to the quantitative description and a research of processes of functioning of various S. of an organism modeling (see). Special range of application of systems approach is represented by studying of interaction of the person with various technical devices and cars — so-called systems of people — the car (see. «person — the car» System ).

Use of ideas of S. in medical practice is connected with with emergence of new methods of treatment and the maintenance of Life activity (an intensive care, artificial organs) demanding special quantitative control facilities and management (see. Information retrieval system ), and creation of various types of the automated S. (see. Automated control system ).

Bibliography: Anokhin P. K. Nodal questions of the theory of functional system, M., 1980; Bertalanf of L. The general theory of systems — the critical review, in book: Researches on the general theory of systems, the lane with English, under the editorship of V. N. Sadovsky and E. G. Yudin, page 23, M., 1969; Novoseltsev V. N. Theory of management and biosystem, Analysis of sokhranitelny properties, M., 1978; Problems of methodology of a system research, under the editorship of I. V. Blauberg, etc., M., 1970.

V. N. Novoseltsev.