SISTEMOGENEZ

From Big Medical Encyclopedia

SISTEMOGENEZ (Greek systema the whole, made of parts + by genesis origin) — process of morfofunktsionalny formation in pre-and the post-natal periods of ontogenesis of the functional systems providing a possibility of adaptation of an organism to conditions of the environment. S.'s concept was created by P. K. Anokhin. By its definition, S. is the selective and accelerated on rates development in an embryogenesis various on quality and localization of textural features, to-rye, being consolidated in general, integrate the full-fledged functional systems providing to the newborn survival. Such electoral association of diverse structures of an organism in functional systems, in turn, becomes possible only on the basis of a geterokhroniya in bookmarks and rates of development and in the moments of consolidation of these structures throughout all embryonal period». The doctrine about S. arose in the course of development of the general theory functional systems (see).

P. K. Anokhin came to a conclusion that S. is one of the general patterns of evolutionary process. The parallel research of structure and function of the developing organism of various animals, birds and a fruit of the person showed that idea of formation of functional systems in an embryogenesis essentially differs from the standard explanation of process of maturing on the basis of the principle organogenesis (see). In the embryonal period there is a selective development of a number of structures or their parts, various on localization and anatomic bonds, to-rye, combining, form vital for the developing organism of system, adapting it for new living conditions. A characteristic sign of this development is the geterokhronnost, i.e. distinctions in time of a bookmark and speed of maturing of structures in the course of their association in system. Two types of geterokhroniya — intrasystem and intersystem are allocated. So, laying of kernels of the facial and trigeminal nerves which are a part of the system suctions, providing maintenance of life of the newborn, occurs laying of kernels of other cranial nerves much earlier — at a stage of not closed neurotubule. Myelination of the facial nerve making an effector component of this system develops with various speed (the so-called principle of fragmentation of body). First of all the branches going to muscles of a mouth are myelinized to-rye provide the act suctions (see). It is characteristic, as these branches are myelinized not equally in time (an intrasystem geterokhroniya). Later myelination of the frontal branches and branches innervating mimic muscles (the principle of an intersystem geterokhroniya) begins. In the same sequence there is a cytologic differentiation of cells of a kernel of a facial nerve. By the time of the birth the system of suction is rather ripened and is capable to provide survival of the newborn (the principle of the minimum providing). However improvement of this system continues also in the post-natal period due to formation of new bonds by the principle conditioned reflex (see). Even more visually the phenomena of a geterokhroniya are traced on the example of development of motor cells of a spinal cord, the innervating muscle of hands and a shoulder girdle of a fruit of the person. Before all nervous cells, the innervating muscles of a brush ripen, to-rye hands — a grasp reflex perform the earliest function. At the same time the law of proksimodistal-ny development is broken. So, nervous cells of a spinal cord, the innervating sgibatel of fingers, ripen earlier, than the cells innervating a deltoid muscle. The same maturing of conduction paths, selective on time, is observed during the merging of separate structures in the complete system yielding adaptive result (the principle of consolidation). It is shown that collaterals of the descending nerve pathways from a brainstem burgeon to the motor-neurons of a spinal cord innervating a brush, earlier than the collaterals going to the nervous cells innervating the deltoid muscle located more proksimalno. Thus, morphological development of a germ is carried out not by the principle of an organogenesis, and due to selective maturing of those parts of any body, to-rye participate in adaptive activity of a fruit and the newborn.

The page as the general pattern of development is most accurately shown in the period of an embryogenesis. However and in post-natal life there is a continuous development of an organism to consecutive and step-by-step inclusion and change of its functional systems providing adaptation to the changing conditions of the environment. In this period change of the leading afferentation is especially accurately expressed. At each stage of formation of functional system one of the afferentation participating in afferent synthesis (see), is dominating, and at the subsequent stages it is replaced by afferentation of other modalities. So, in feeding responses of baby birds of a rook and a flycatcher rainbow trout in the first days of life the leading afferentation is acoustical, the value further conducting is gained by a visual, and then tactile afferen-tation.

It is shown that the principles C. are applicable to development of a brain. It turned out, in particular, that the caused bioelectric potential registered in a cerebral cortex is on the structure and an origin slozhnsh a phenomenon. It forms the ascending vozbuzhdeniye having various fiziol. the nature and going from different subcrustal structures. The last throughout ontogenesis develop geterokhronno and are characterized by a sharp geterokhroniya in phylogenesis. So, the cytologic differentiation of cells of primary visual centers of an interstitial brain occurs after cells of pretektalny area, but before a differentiation of cells of bark of front hillocks a chetverokholmiya. Most the cells of a reticular formation of a mesencephalon perceiving feeling of light (the principle of an intra-touch geterokhroniya) are early differentiated. The Geterokhronnost of maturing is inherent also to cells of various layers of bark and the fibers which are going back to them. Similar ratios are inherent in sensomotor area of bark in the course of maturing of defensive and locomotory systems; distinctions in the speed of their maturing (the principle of an intertouch geterokhroniya) are established. Considerable heterogeneity hikhm is found. properties of a postsynaptic membrane of a nervous cell. The defining participation of adrenergic substances and glutaminic to - you in implementation of motive function at early stages of ontogenesis was revealed.

Mechanisms C. are investigated on different objects and at the different levels of the organization of vital processes. So, in culture of fabrics stability of nervous bonds in cellular transplants and pattern of their association in system is studied. The principles of the minimum providing and a geterokhroniya are investigated at the cellular and subcellular levels. At the same time features of formation of nervous impulse of an unripe nervous cell were established. It turned out that the action potential of such cell does not submit to the law «everything or nothing», its duration and amplitude depend on irritation. It is explained by a geterokhronnost of maturing of a somatodendritny membrane and an initial segment of an axon, and also features of development of dendrites. During the studying of synoptic mechanisms of process of consolidation of system it was suggested that command neurons of a reticular formation of a brainstem send high-frequency excitement, the defiant phenomena a poten-cyathium in target cells of a spinal cord thanks to what in them emergence of a spike discharge is facilitated.

At the nadorganizmenny level within micropopulation (e.g., at a brood of baby birds) the new obligatory factor of S. — the synchronous and accelerated development of the main components of functional system in the conditions of the enriched environment is allocated. It is shown that increase in external influences leads to progressive acceleration of maturing of baby birds and to more bystry change of critical periods of development. In the conditions as close as possible to natural, formation of system of a pi-shchedobyvaniye is tracked at losit since first days of life. The sistemoformiruyushchy role of the first successful suction, i.e. a role of the first result of action is shown. It is supposed that in inborn acceptor of result of action (see) there are only most general parameters of future behavior. The first receiving milk a losenok consolidates all separate elements of behavior in complete system of suction, edges in the subsequent there passes a number of stages with signs of emotional pressure, inherent for each stage. The elk cow and her newborn are considered at the same time as uniform biosystem.

In the course of long evolution from the elementary forms to the person the live organism gained ability to reflect periodically repeating phenomena of the outside world in the design. Improvement of this property and all mechanisms of information transfer from the environment led to emergence of ability of an organism to advance these phenomena and to adapt to them long before their beginning. In the period of an embryogenesis there is a development of those functional systems, to-rye are necessary for implementation of the vital functions of the newborn adapting it for conditions of the environment, specific to it. Therefore for each species of an animal there is a specific set early of the ripening functional systems, therefore, peculiar sistemogenez.

Owing to various diseases of a pregnant animal at a fruit disturbance of development of the main vital systems is observed that leads to his death. So, damage of the cells of a reticular formation of a mesencephalon participating in regulation of breath leads to development of pre-natal asphyxia or to asphyxia at the birth that can cause death of a fruit. At the newborn child it causes development of a number patol. the phenomena (mental or physical retardation, shortcomings of the speech, disturbance in the motive sphere, etc.), and in some cases can lead to death, napr, at dysfunction of suction.

See also Brain .



Bibliography: Anokhin P. K. Biology and neurophysiology of a conditioned reflex, page. And, 76, M., 1968; it sh e, Sketches on physiology of functional systems, page 273, M., 1975; it, Chosen works, page 125, M., 1978; Ata - Moura - d about in and F. A. The developing brain, Systems analysis, M., 1980; Golubeva E. JI. Formation of the central mechanisms of regulation of breath in ontogenesis, M., 1971; Neural mechanisms of the developing brain, under the editorship of K. V. Shue-leykinoy and S. N. Hayutin, M., 1979; Si-stemogenez, under the editorship of K. V. Sudakov, M., 1980; Hayutin S. N. and Dmitriyeva L. P. Organization of natural behavior of baby birds, M., 1981; Sh at l e K. V fi-kina. System organization of a feeding behavior, M., 1971; Shumilina A. I., Bogomolova E. M and Kurochkin Yu. A. Dynamic properties of the system organization of purposeful behavior, Vestn. USSR Academy of Medical Sciences, No. 2, page 26, 1982.


E. L. Golubeva.

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