From Big Medical Encyclopedia

REFLEXOGENIC ZONES (Latin reflexus turned back, reflected-) - Greek gennao to create, make; synonym receptor fields, receptive fields) — the areas of a body including set of receptors, adequate irritation to-rykh are caused by a certain reflex. The concept «reflexogenic zones» is applied, as a rule, to to instinctive reflexes (see). E.g., the mucous membrane of a trachea and bronchial tubes is R. z. a tussive reflex, a mucous membrane of a nose — R. z. a reflex of sneezing, a cornea of an eye — a blink reflex etc.

R. z. have all bodies and body tissues. With their help continuous control of internal environment of an organism and close interaction of its functional systems is exercised. Thus, R. z. play an important role not only in maintenance of a homeostasis, but also in ensuring life activity of an organism in the course of its continuous contact with the environment.

Concept P. z. it is closely connected with a concept receptions (see) and receptor (see). Therefore by analogy with them distinguish ekstero-, proprio-and interoceptive zones, originative to various somatic and vegetative reflexes. Depending on a modality irritant (see) allocate mekhano-, thermo - chemo - and other R. z.

Functional and structural organization P. z. in each body and fabric has specifics, as defines features of response.

Among R. z. internals special position is held by aortal and carotid R. z., the including R. z. aortic arches and sinocarotid zone. The sinocarotid zone is located in the place of a branching of the general carotid artery (see) on outside and internal also consists of two educations — a carotid sine and a carotid ball. The carotid sine is specially innervated part of a vessel, in a cover to-ro-go the baroreceptors which are a source of pressotseptivny reflexes are located. In a carotid ball are located chemoceptors (see), blood, sensitive to change of gas structure. The Sinkarotidny zone is important in regulation of metabolism and providing a homeostasis in an organism. In particular, the excitement of baroreceptors of a carotid sine accompanying increase in arterial pressure causes a so-called vazokardialny reflex (Bainbridge reflex) which is in vasodilatation and delay of heartbeat that leads, in turn, to decrease arterial pressure (see). Pressotseptivny and hemotseptivny reflexes of this zone exert strong impact and on activity respiratory center (see). Allocate also so-called motor and visceral reflexes, with the help to-rykh muscular contractions through proprioceptive afferent system reflex can regulate vegetative and visceral functions. In particular, skeletal muscles with its proprioception (see. Proprioceptors ) is powerful R. z. for internals.

Spatially - the functional organization of separate R. z. depends on age, sexual and genetic features of an organism, and also on the sequence of maturing of separate links of a nervous system in the course of an ontogeny. Accurate dynamics of formation of R. z. in ontogenesis it is visible on the example of a sucking reflex. River z. a sucking reflex it is most extensive at a fruit — takes all head and a neck; at the newborn the area it is narrowed, being limited to cheeks and a chin, and in two-three weeks after the birth the sucking reflex is caused only at irritation of lips. At the healthy adult the sucking reflex is not caused, emergence specifies it on patol. changes in a nervous system.

Studying of distribution of R. z. (expansions, narrowings and asymmetries), carried out with the help refleksometriya (see), has great diagnostic value in clinic of nervous diseases. That fact that R. z. take essential part in regulation of life activity of an organism, allows to use various impacts on these zones with the medical purpose (see. Reflexotherapy ).

River z. and their properties are investigated by various methods of the functional and structural analysis, including morphological techniques, registration of bioelectric activity of receptors of R. z., and also registration of the reflex reactions arising at R.'s irritation z.

Bibliography: Bulygin I. A. Afferent link of interoceptive reflexes, Minsk, 1971, bibliogr.; Lips - m and N of JI. B. Age dynamics of reflex interaction of motor and visceral functions, Kalinin, 1975; Samoylov V. O. Some problems of carotid chemoreception, in book: Touch systems, under the editorship of G. V. Gershuni, page 76, L., 1977; Physiology of touch systems, under the editorship of G. V. Gershuni, p.1 — 2, L., 1971 — 1972; HeggelundP. Receptive field organization of simple cells in cat striate cortex, Exp. Brain Res., v. 42, p. 89, 1981; it, Receptive field organization of complex cells in cat striate cortex, ibid., p. 99.

A. M. Ivanitsky, T. D. Filimonova.