PROTECTIVE REFLEXES

From Big Medical Encyclopedia

PROTECTIVE REFLEXES (synonym: protective, or defensive, reflexes, reflex synergies, medullary automatism) — the reactions arising at impact on an organism of the irritants breaking its normal activity harmful to it or life-threatening. 3. river — one of versions defense reactions of an organism (see).

See also Instinctive reflex , Adaptive reactions , Reflex , Conditioned reflex .

PROTECTIVE REFLEXES in pathology

PROTECTIVE REFLEXES in pathology are the difficult involuntary movements of paretichny parts of a body arising in response to irritation of skin or deep fabrics; they serve as manifestation of spinal automatism at switching off central (pyramidal and extrapyramidal influences). To distinguish 3. the ruble from actually cutaneous reflexes offered A. van Gehuchten.

From tendinous 3. rubles differ as way, them cause the Crimea, and character of motor reaction. The muscular groups innervated from several next segments of a spinal cord are involved in the difficult movement of an extremity.

Cause 3. river different receptions: the shaped movement of a needle on skin, pricks, tingling of skin, a strong prelum of soft tissues, cooling of skin (a piece of ice, drops of ether), the faradic current forced by a muscle strain. After emergence 3. the river comes a short refractory phase, in time a cut 3. the ruble does not manage to be caused. At repeated researches 3. the ruble is called easier and easier each time. For receiving 3. rubles standing irritate skin of a sole, foot, a hip, a stomach; on hands — skin of a palm, a forearm, a breast (a dermatoma of Th2 — Th5) or strongly squeeze a big pectoral muscle in an axillary pole.

Motive manifestations 3. rubles are diverse, but at one patient are usually stereotypic. On character of motor reaction allocate two main types 3. river. Flexion type — bending of a leg in coxofemoral and knee joints in combination with a dorsiflexion of foot or bending of a hand in elbow and radiocarpal joints; leads to shortening of an extremity. Such 3. the river arises at distal drawing irritation more often. Extensive type — extension of a leg in coxofemoral and knee joints in combination with bottom bending of foot or extension of a hand in elbow and radiocarpal joints; leads to lengthening of an extremity. More often it turns out at proximal irritation. It is easier to cause an extensive reflex at slightly bent position of an extremity. On a leg there are also more irregular shapes 3. river: bending is combined with rotation of a hip inside and assignment of foot, and extension with rotation of a hip of a knaruzha and reduction of foot. At strong development 3. the river can flow in two phases — shortening is replaced by lengthening.

About expressiveness 3. rubles judge by the area of a receptor zone (zones, irritation the cut can cause 3. ruble), on number involved in the reflex act of muscular groups and also on ease of emergence 3. river.

Upper bound of a receptor zone 3. the river can reach the skin dermatome corresponding to the lower level of the center in a spinal cord. Comparing this level with the top level of the center defined on the basis of disorders of sensitivity establish the extent of damage of a spinal cord. At heavy cerebral pathology the receptor zone can extend to all struck half of a body up to an auricle.

About expressiveness 3. the river testifies cross generalization — calling of a reflex on one leg leads to its bending and at the same time extension of other leg which is previously passively bent (crossed reflex, a reflex of walking, a reflex of Sherrington). At longitudinal generalization along with reflex bending or extension of a leg there comes the involuntary tonic muscle tension of a hand or at reflex bending of a hand there is a tonic muscle tension of a leg. Distribution of tonic tension on muscles of a trunk, a front abdominal wall (a mass reflex) quite often is followed by an involuntary urination and a passage of flatus.

The clinic causes the following options 3 more often. river. A bending reflex of Bekhterev — Mari — Fua — bending of a leg in three joints at passive bottom bending of fingers and feet. Girshberg's reflex — the reduction and bottom bending of foot arising at shaped irritation and a pricking of skin of an inner edge of a sole and at the basis of a thumb. Remak's reflex (femoral) — the bottom bending of foot and fingers in combination with extension in a knee joint coming at shaped irritation of skin of an anteriointernal surface of an upper third of a hip.

3. rubles in legs reach the greatest expressiveness at tumors, an injury of a spinal cord, a cross myelitis, multiple sclerosis, a family spastic paraplegia (Shtryumpell's disease), Fridreykh's disease, a side amyotrophic sclerosis. At defeat of pyramidal and extrapyramidal ways in a brain 3. rubles appear in hands more often. The necrotic centers in a trunk of a brain and subcrustal nodes are followed by reflexes of extensive type, and at the centers in bark of big hemispheres and adjacent white matter — flexion type. 3. rubles appear also at vascular, inflammatory, traumatic and tumoral damage of a brain, especially against the background of coma. In case of the favorable course of a disease expressiveness 3. the river decreases.

See also Instinctive reflex , Reflexes pathological .



Bibliography: Bekhterev V. M. The general fundamentals of reflexology of the person, M. — L., 1928, bibliogr.; Bogolepov N. K. Disturbance of motive functions at. vascular damages of a brain, M., 1953, bibliogr.; Granite P. Bases of regulation of movements, the lane with English, M., 1973, bibliogr.; Davidenkov S. N. Protective reflexes, Alexandria, 1918; M. B. and Fedorov E. A. Crawl. Main neuropathological syndromes, M., 1966; Babin-s k i J. Paraplegie spasmodique organique avec contracture en flexion et contractions musculaires involontaires, Rev. neu-rol., t. 21, p. 132, 1911; Marie P. et F o i x G h. Les of r£flexes d’automatisme medullaire et les of ph£nomenes des raccou-rcisseurs, ibid., t. 22, p. 657, 1912.

B. H. Rod.

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