Endoplasmic network

The endoplasmic network was opened by K.R. Porter in 1945. This membrane organella of general purpose represents set a vacuole, the flat membrane bags or tubular educations creating as if a membrane network in cytoplasm. Distinguish two types — a granular (rough) and smooth endoplasmic network.

The granular endoplasmic network (reticulum endoplasmaticum granulosum) is presented by the closed membranes which form the flattened bags, tanks, tubules. Width of cavities of tanks considerably varies depending on functional activity of a cage. Their smallest width — about 20 nanometers, but they can reach diameter in some micrometers. A distinctive feature of membranes of granular EPS is that they from a gialoplazma are covered with ribosomes (fig. 8).

The granular endoplasmic network is presented by rare separate tanks or their local congestions. The first type of a granular endoplasmic network, is characteristic for low-specialized a ktetok or for cages with low metabolic activity. Congestions of an endoplasmic network are accessory of the cages which are actively synthesizing sekretorny proteins. So, in cells of a liver and some nervous cages the granular endoplasmic network is collected in separate zones. In cells of a pancreas the granular endoplasmic network in the form of the membrane tanks which are densely packed the friend about the friend occupies bazalny and okoloyaderny zones of a cage.

The ribosomes connected with membranes of an endoplasmic network participate in synthesis of the proteins removed from this cage (the "exported" proteins). Besides, the granular endoplasmic network takes part in synthesis of proteins — the enzymes necessary for the organization of an intracellular metabolism, and also used for intracellular digestion.

The role of a granular endoplasmic network consists in synthesis on its ribosomes of the exported proteins, in their isolation from gialoplazma contents in membrane cavities, in transport of these proteins in other sites of a cage, in chemical modification of such proteins and in their local condensation, and also in synthesis of structural components of cellular membranes.

The Agranulyarny (smooth) endoplasmic network (reticulum endoplasmaticum nongranulosum) is also presented by the membranes forming small vacuoles and tubes, tubules which can branch, merge with each other. Unlike a granular endoplasmic network on membranes of a smooth endoplasmic network there are no ribosomes. Diameter vacuole and tubules of a smooth endoplasmic network usually about 50 — 100 nanometers.

The smooth endoplasmic network arises and develops at the expense of a granular endoplasmic network (at release it from ribosomes).

Activity of a smooth endoplasmic network is connected with a metabolism of lipids and some

The role of a smooth endoplasmic network in deactivation of various substances, harmful to an organism, due to their oxidation by means of a number of special enzymes is very important. Especially accurately it is shown in cells of a liver. So, at a number of poisonings in cells of a liver there are acidophile zones (which aren't containing RNA), entirely occupied with a smooth endoplasmic retikulum.

Не знайшли потрібну інформацію? Скористайтесь пошуком google:

Генерація сторінки за: 0.005 сек.