GIPOTALAMO-GIPOFIZARNAYA SYSTEM

From Big Medical Encyclopedia

GIPOTALAMO-GIPOFIZARNAYA SYSTEM — the functional complex consisting of hypothalamic area of a diencephalon and a hypophysis.

The principal functional value of gipotalamo-pituitary system — regulation of vegetative functions of an organism. From a hypothalamus it is carried out in the paraadenogipofizarny way, passing an adenohypophysis, and a transadenogipofizarny way through an adenohypophysis when vegetative functions are regulated through a complex of the peripheral, endocrine glands targets dependent on a hypophysis. There is still parapituitary, purely neuroconduction way which is implemented through system of efferent central neurons of a trunk of a brain and spinal cord, peripheral sympathetic and parasympathetic neurons.

An essential contribution to studying of morphology, physiology and G.'s pathology - of page domestic scientists N. M. Itsenko, L. Ya. Pines, N. I. Grashchenkov and foreign researchers S. Ramone-and-Kakhal brought, X. Cushing, R. Greving, Sharrer (E. Scharrer), J. Szentagothai, etc.

G. - of page is formed by two genetically different parts — hypothalamus (see) and hypophysis (see).

With age the involutional changes which are expressed reduction of number of neurosecretory cells of a hypothalamus and a hypophysis, their partial are observed pycnosis (see), change of distribution of tigroid substance, various changes of nervous cells that leads to decrease in secretory activity.

According to some authors, the main structural and functional components G. - of page are two sorts of nervous cells: neurosecretory — the developing peptides (peptidergichesky neurons) and the cells cosecreting monoamines (monoaminergichesky neurons). The neurosecretory cells producing peptide neurohormones form macrocellular kernels: nadzritelny (nucleus supraopticus), okolozheludochkovy (nucleus paraventricularis) and back (nucleus post.) kernels.

Gomoripolozhitelny cells — the largest elements in a hypothalamus, sometimes multinuclear, huge therefore neurosecretory formations received the name of the macrocellular centers (kernels), unlike other small-celled kernels of a hypothalamus. The neurosecretion developed by these cells is painted by chromic hematoxylin or paraldegidfuksiny by Gomori's method and is called gomoripolozhitelny. It is defined by Elektronnomikroskopicheski in bodies and shoots of these cells, but especially in nerve terminations (terminalyakh) of axons in the form of elementary granules of two sizes: 100 — 150 nanometers (1000 — 1500 And) and 150 — 300 nanometers (1500 — 3000 And). The neurosecretion which is synthesized in a neuroplasm (perikaryons) of neurosecretory cells moves with current of a neuroplasm to terminal departments of shoots. The ground mass of granules comes to a back share of a hypophysis. Here terminal departments of axons of neurosecretory cells (the neurosecretory terminations) form contacts with capillaries.

Thanks to big accumulation of the terminations of axons and capillaries in a neurohypophysis this part of gipotalamo-pituitary neurosecretory system received the name of neyrogemalny body.

However in a modern neuroendocrinology the opinion prevails that neurosecretory formations of a hypothalamus are presented not only gomoripolozhitelny cells which are cholinergic and produce oktopeptidny neurohormones (vasopressin and oxytocin). Along with gomoripolozhitelny cells of a front hypothalamus the second group is made by the small neurosecretory cells of the adrenergic nature which are localized in a mediobazalny hypothalamus (an adenogipofizotropny zone) and forming nechetkoogranichenny kernels: front hypothalamic (nucleus hupothalamicus ant.), suprakhiazmatichesky (nucleus suprachiasmaticus) of a kernel and preoptichesky zone (zona praeopticus); arkuatny, or infundibulyarny (nucleus arcuatus, nucleus infundibularis), periventrikulyarny kernels (nuclei periventriculares, anr. et post.), ventro-medial (nucleus ventromedialis) and dorsomedial (nucleus dorsomedialis) of a kernel. They produce oligopeptidny hormones (see. Hypothalamic neurohormones ). Secretion of their (rileasing-hormones) is regulated mainly by a ratio of concentration of noradrenaline, acetylcholine and serotonin in a hypothalamus.

The general morfo-functional sign of all departments of a neurohypophysis is that in them on numerous capillaries bombways neurosecretory peptidergichesky, adrenergic terminate and, according to some researchers as well cholinergic fibers. The glial stroma of a neurohypophysis is presented by the pituicytes (a cell of a neuroglia) providing a trophicity of nerve fibrils and their bombways; ability of these cells to phagocytosis is described, in particular absorption is noted by these cells of products of metabolism.

G.'s blood circulation - of page is presented by the rich network of capillaries which is formed at the expense of front and back pituitary arteries of system of an arterial circle of a brain (see. Hypophysis ).

Information on a functional condition of visceral bodies and internal environment of an organism, and also on the changes happening in external environment comes respectively from intero-and eksteroretseptor preferential to the centers of a mesencephalon, in particular to a reticular formation, and from there already to a hypothalamus. Thin integration of vegetative functions of an organism is carried out by the highest departments of c. N of page, napr, limbic system. From all specified departments of a brain impulses on numerous conductors arrive on neurosecretory cells. All neurosecretory peptidergichesky cells represent an end efferent body in implementation of nervous influences on activity of an adenohypophysis and visceral bodies, including and endocrine glands targets.

The importance in the neuroendocrinal relations belongs to feed-backs among which differ «short» (an adenohypophysis — a hypothalamus) and «long» bonds (glands targets — a hypothalamus). Thanks to these bonds as a part of the whole organism self-control of a neuroendocrinal complex is carried out. So, regulatory influence of both triple hormones of an adenohypophysis, and hormones of peripheral glands on intensity of products in perikaryons of neurosecretory cells and allocation from bombways of their axons, adenogipofizotropny is allowed, and, it is possible as well viscerotropic peptide neurohormones.

The considered unity of a complex a hypothalamus — a hypophysis is brightly shown at its pathology. It is expressed in difficulty of a differentiation of localization patol, processes (in a hypothalamus or in a hypophysis).

Only in case of existence of separate adenomas it is possible to find out local defeat of an adenohypophysis. The damages to gipotalamo-pituitary system caused by infectious processes, new growths, or at an injury of a skull and brain, leading to local impact on the centers of a hypothalamus or to disturbance of integrity of gipotalamo-pituitary bonds, usually lead to deep and permanent disturbances of various parties of a metabolism (water-salt, fatty, carbohydrate), to disturbance of thermal control, function of generative organs and decrease in body resistance (see. Hypothalamic syndrome ). And studied the following diseases are the most characteristic: diabetes not sugar (see), pituitary cachexia (see) and Itsenko — Cushing a disease (see). Sometimes at defeat of a gray hillock develops also diabetes mellitus (see).



Bibliography: Alyoshin of B. V. Giotofiziologiya of gipotalamo-pituitary system, M., 1971, bibliogr.; Voytkevich A. A. Neurosecretion, L., 1967, bibliogr.; Polenov A. L. Hypothalamic neurosecretion, L., 1971, bibliogr.; Polenov A. L. and White M. A. O some patterns of formation of neyrogemalny departments of gipotalamo-pituitary neurosecretory system in onto-and phylogenesis of vertebrata, Zhurn, evolyuts, biochemical, and fiziol., t. 9, No. 4, page 355, 1973, bibliogr.; Thin A. V. Gipotalamo-gipofizarnaya area and regulation of physiological functions of an organism, M. — L., 1965, bibliogr.; Aspects of neuroendocrinology, ed. by W. Bargmanna. B. Scharrer, Heidelberg — N. Y., 1970; Bargmann W. Neurosecretion, Int. Rev. Cytol., v. 19, p. 183, 1966, bibliogr.; Scharrer E. Scharrer B. Neuroendocrinology, N. Y. — L., 1963, bibliogr.

B. V. Alyoshin, A. L. Polenov.

Яндекс.Метрика