ENDOCRINE SYSTEM

From Big Medical Encyclopedia

ENDOCRINE SYSTEM (Greek endon inside + krino to separate, allocate) — the system consisting of the specialized structures located in the central nervous system, various bodies and fabrics and also the hemadens producing specific biologically active agents (hormones). Along with a nervous system E. the page participates in regulation of functions of various systems, bodies and metabolic processes.

The regulating influence E. the page carries out through hormones (see), for to-rykh are characteristic high biol. activity (they have effect in concentration 10-11 — 10 ~ 7 M) and a distantnost of action (far from the place of education). Biol. value of hormones consists in humoral ensuring coordination and integration of processes of life activity of an organism: growth, development, reproduction, adaptation, behavior (see. Hormonal regulation, Humoral regulation).

Carry to endocrine system of the person: secretory kernels of a hypothalamus (see), the hypophysis (see), a pinus (see), a thyroid gland (see), a thymus (see), epithelial bodies (see), adrenal glands (see), male and female gonads (see Gonads), endocrine departments of a pancreas (see) also went. - kish. path.

AA. page arose at the earliest stages of evolution of metazoans. Existence of neuroendocrinal functions is found already in coelenterates. Development E. the page was characterized by complication of a structure, function, change of topography of hemadens, and also chemical structures of hormones, especially proteinaceous and peptide (see. Proteinaceous and peptide hormones).

Bookmark, differentiation in functioning E. pages occur at early stages of an embryogenesis. In the post-natal period further development, and also integration of hormonal effects is observed. By the time of the birth of the child all links E. pages are morphologically created, but the sizes, a form, weight and their microvery tectonics are exposed in the course of post-natal development to considerable transformations. In the first years of life age changes of all bodies E. pages are characterized by a further differentiation of the structures responsible for specific function, and also snowballing of intraorganic blood vessels and stromas. During from 5 to 8 years rates of structural transformations decrease. The beginning of puberty is preceded by considerable changes of a structure of a hypophysis that leads to strengthening of its gonadotropic function. By 11 years correlation ratios between separate bodies and intersystem bonds amplify. In gonads at girls the quantity of mature follicles increases, yellow bodies appear; gonads at boys are differentiated, in them spermatozoa are formed. During from 11 to 14 years structural transformations happen in an adenohypophysis, adrenal glands, thyroid and gonads. By 16 years a structure of bodies E. the page is close to their structure at people of mature age.

In endocrine system allocate the central link — secretory kernels of a hypothalamus, a pinus, to-rye obtain information from c. N of page and by means of neurosecretion switch it to the adenohypophysis which is directly participating in regulation of endocrine organs, dependent on it. Peripheral link E. pages make: 1) glands dependent on an adenohypophysis: a thyroid gland, bark of adrenal glands, and also gonads — an ovary (see) and a small egg (see); 2) glands not dependent on an adenohypophysis: a brain part of adrenal glands, epithelial bodies, okolofollikulyarny cells of a thyroid gland, and and | 3-klet-ki islands of a pancreas, and also gormonprodutsiruyushchy cells went. - kish. path, thymus.

The special place in E. the page is occupied by the gipotalamo-pituitary system (see) which is carrying out functions of «an endocrine brain». The hypothalamus in response to nervous impulses and action of mediators forms the hypothalamic neurohormones (see) rendering stimulating (rileasing-hormones, or liberina) or tormo-

zyashchy (statines) action on a front share of a hypophysis. Hypothalamic neurohormones are specialized and regulate production of certain hormones of a hypophysis: tiroli-Berinum and tirostatin — TTG (see Ti-reopgropny hormone), somatoliberin and somatostatin — STG (see Somato-tpropny hormone). Through hypophyseal hormones the hypothalamus regulates function of peripheral hemadens (see). So, tiroliberin a hypothalamus at first excites secretion of TTG of a hypophysis, and the last, in turn, stimulates secretion with a thyroid gland of thyroid hormones. Regulation of secretion of bark of adrenal glands on a functional axis kortikolibe-rin-adrenocorticotropic hormone — glucocorticoids is in the same way carried out. In this regard it is accepted to speak about uniform functional systems: a hypothalamus —

a hypophysis — a thyroid gland, a hypothalamus — a hypophysis — adrenal glands. A basis of regulation of such systems is the principle of a positive or negative feed-back (see the Feed-back). At the same time in the hypothalamus are synthesized, and then the nek-ry hormones collecting in a back share of a hypophysis cosecrete: vasopressin (see), oxytocin (see).

AA. the page includes also peripheral hemadens and extrahypothalamic regulatory complexes, napr, system a renin — angiotensin — Aldosteronum (see Aldosteronum, Angiotensin), metabolic regulation (influence of content of glucose in blood on secretion of insulin islands of a pancreas), specialized mechanisms of transport of hormones (transport tran-skortin proteins, tiroksinsvyazyvayushchy proteins, etc.), peripheral exchange of hormones and that is especially important, reception of hormones target cells. Receptor specific proteins cause selective reception, transformation and initiation of action of a hormonal signal (see Receptors). Thus, each of components of hormonal regulation is of great importance and loss it from the general system leads to development various patol. states.

Pathology E. the page is expressed by various diseases and patol. states, to-rykh hyperfunction, hypofunction or dysfunction of hemadens are the cornerstone. As a rule, for pathology E. pages are characteristic dysfunctions of several closed glands that is connected with features of their regulation. Diseases of the separate closed glands relating to a peripheral link E. pages, divide on primary (defeats of the gland), secondary (the dysfunction of gland connected with damage of a hypophysis) and tertiary (the dysfunction of gland connected with defeats of a hypothalamus).

Etiology and pathogeny of many diseases E. pages remain in many respects still insufficiently studied. Pathology E. the page can be connected with disturbances of an embryogenesis, genetic and chromosomal anomalies, inflammatory and tumoral processes, immunol. frustration, injuries, disturbances of blood supply, damages of various parts of the nervous system, disturbance of fabric sensitivity to hormones. Among the most widespread diseases E. the village should note a diabetes mellitus (see a diabetes mellitus), obesity (see), a local craw (see the Craw local), a diffusion toxic craw (see the Craw diffusion toxic), a hypothyroidism (see) and dysfunction of gonads (see the Small egg, Ovaries).

See also Hemadens, Endocrinology.

Bibliography: And yes p and Ya. I. Nerves of hemadens and mediators in regulation of endocrine functions, M., 1981; Alyoshin of B. V. Gistofiziologiya of gipotalamo-pituitary system, M., 1971; Biochemistry of hormones and hormonal regulation, under the editorship of N. A. Yudayev, M., 1976; Volkova O. V. and Baking M. I. Embriogenez and age histology of internals of the person, M., 1976; Yefimov A. S., Baud

of plank beds P. N. and Zelinsky B. A. Endokrinologiya, Kiev, 1983; Levina S. E. Formation of endocrine system in prenatal development of the person, M., 1976, bibliogr.; R about z e V. B N. Fundamentals of endocrinology, M., 1984; R ozenas V. B. and Smirnov A. N. Receptors and steroid hormones, M., 1981; The Guide to clinical endocrinology, under the editorship of V. G. Baranov, JI., 1977; The Guide to endocrinology, under the editorship of B. V. Alyoshin, etc., M., 1973; Starkova H. T. Clinical endocrinology, M., 1983; Physiology of development of the child, under the editorship of V. I. Kozlov and D. A. Farber, page 196, M., 1983; Physiology of endocrine system, under the editorship of V. G. Baranov, etc., JI., 1979; Endocrinology and metabolism, under the editorship of F. Feliga, etc., the lane with English, t. 1 — 2, M., 1985; Hormones in blood, ed. by of Page H. Gray a. V. H. T. James, v. 1—5, L., 1979 — 1983;

Lab-hart A. Klinik der inneren Sekretion, B. — N. Y., 1971; Textbook of endocrinology, ed. by R. H. Williams, Philadelphia a. o., 1981.

V. B. Rosen, L. K. Semenova.

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