From Big Medical Encyclopedia

MUCOUS MEMBRANE [tunica mucosa (PNA, BNA)] — an internal cover of the hollow bodies which are reported with external environment (a respiratory organs, uric, sexual and digestive systems).

The village of the lake of various bodies consists of an epithelium (epithelium), own plate (lamina propria) and a muscular plate (lamina muscularis), prilezhit edges to a submucosa (tela submucosa) separating S. of the lake from other layers of a wall of body (e.g., from a muscular coat). In the drawing the schematic structure of S. of the lake is shown. The mucosal surface of a cover is always covered with slime (mucus).

Diagrammatic representation of a structure of a mucous membrane: I \epithelium; II \own plate; III \muscular plate; IV \submucosa; 1 — a nervous stipitate; 2 — neuroplex; 3 — complex (alveolar and tubular) glands; 4 - simple tubular glands; 5 — a lymphoid follicle; 6 — a venous vessel; 7 — absorbent vessel; 8 — an arterial vessel.

Villages of the lake of various vertebrata have a number of structural and histochemical features. So, at amphibians and reptiles S. of the lake of a gullet is covered by a multirow ciliary epithelium, and at mammals (including the person) — multilayer flat. There are distinctions (depending on type of food) in the histochemical characteristic of an epithelium of S. of the lake of a stomach of mammals. So, at carnivorous neutral glycoproteins, sialoglikoproteida, sul-foglikoproteida, and at vegetable — only neutral glycoproteins are its part.

Fabric components C. of the lake come from various embryonal rudiments. The epithelium develops from all three germinal leaves (see): a multilayer flat not keratosic epithelium of S. of the lake of an oral cavity, anal department of a rectum, vagina and neck of uterus — from an ectodermal germinal leaf; a single-layer epithelium of S. of the lake of a stomach, intestines, gall bladder — from entodermalny; a single-layer epithelium of S. of the lake of a genital tract — from mesodermal; circulatory and limf, vessels, own and muscular plates of S. of the lake — from a mesenchyma.

S.'s epithelium of the lake protects an organism from penetration of harmful substances from the outside and provides a metabolism of an organism with the environment. The structure of an epithelium of various bodies varies depending on functional specifics of S. of the lake. The mucous membrane performing function of protection of a wall of body against the rough, injuring components is covered with not keratosic multilayer flat epithelium (an oral cavity, a throat, a gullet, anal department of a rectum); the mucous membrane providing transport of substances from the environment in an organism or their removal — single-layer (a stomach, intestines).

Own plate of S. of the lake is located directly under an epithelium and consists generally of friable fibrous connecting fabric (see). It contains the powerful intertwining bunches of collagenic fibers in the sites which are exposed to rough mechanical influences (a gum, a hard palate, an epiglottis). In own plate of a mucous membrane it is plentifully developed reticular fabric (see), in a cut are localized single, and in a mucous membrane of an ileal gut — group, or generalized, limf, follicles (a peyerova of a plaque), and also lymphocytes. Lymphocytes possess a leading role in protection of an organism against the bacteria, viruses and other antigenic factors getting into an organism through the epithelium covering S. with the lake. It is shown that in response to an antigenic incentive lymphocytes turn in plasmocytes (see), producing immunoglobulin A (see. Immunoglobulins ), called secretory (SIg A) since it is actively transported on a surface of an epithelium by its secretory cells.

The muscular plate of S. of the lake is formed by smooth neischerchenny muscular tissue (see). Unlike an epithelium and own plate the muscular plate is well-marked only in S. of the lake of bodies alimentary system (see) and bronchial tubes (see).

In other bodies it either is absent, or is presented by separate bunches of smooth myocytes.

The submucosa consists of the friable fibrous connecting fabric providing a possibility of removal of S. of the lake and plication.

The village of the lake has own ferruterous device. One-celled are most widespread mucous glands (see), (endothelial) localized in the epithelium. Usually they are located mosaically, alternating with other epithelial cells (scyphoid cells, endokrinotsita), is more rare groups (panetovsky cells of intestines) or in the form of ferruterous fields (in an epithelium of a stomach and uterus). Mucous glands of own plate multicellular (simple, tubular, more rare branched out).

The vast majority of glands C. the island belong to exocrine (see. Mucous glands ) also develop mucous (more rare proteinaceous) a secret. Being allocated for a surface of an epithelium, slime humidifies it, protects from damage, and in nek-ry bodies adsorbs foreign debris, promoting their removal. Endokrinotsita, panetovsky cells of intestines, tubular glands of a stomach possess more specific functions. Endokrinotsita are found in almost all S.' epithelium of the lake where they form the local endocrine device. As a part of S.'s epithelium of the lake of olfactory area of a nasal cavity there are cells specialized on perception of smells, and in an epithelium of nipples of language — the taste bulbs which are carrying out reception of flavoring agents. In addition to own one-celled glands, on S.'s surface of the lake of an oral cavity, gullet, duodenum, trachea and bronchial tubes output channels of larger glands located in a podslizpsty basis and also the large glands which are independent bodies such as open sialadens (see), liver (see), pancreas (see).

S.'s relief of the lake is defined by its morfofunktsionalny properties. So, S.'s surface of the lake can be smooth (lips, cheeks, a trachea), to form protrusions (fibers of intestines, nipples of language) or emboly (a pole and a crypt in a stomach, intestines, a uterus), folds (a stomach, intestines, a gall bladder, an ureter).

The village of the lake is rich a vaskulyarizirovana at the expense of own vascular textures, a structure to-rykh in different bodies variously, napr, in upper respiratory tracts terminal sites of vascular textures are sharply expanded since they, in addition to participation in metabolism, warm inhaled air. Limf, vessels are most developed in a mucous membrane of intestines.

The nervous device C. of the lake is formed by nerve fibrils of an extra-and int-raorganny origin. And the first are presented by dendrites of neurons of spinal and sensitive nodes craniocereberal (cranial, T.) nerves or a neyritakhma of neurons of sympathetic nodes, and the second — shoots of neurons of intramural nerve knots submucosal and in a smaller measure muscular and intestinal textures.

All fabric elements C. of the lake, but first of all connecting fabric are subject to age changes, in a cut the number of fibrous structures increases (sklerozirovaniye) with age, there are lipoblasts, the quantity circulatory p limf decreases, vessels, and also nerve fibrils per acre, regenerator opportunities of an epithelium decrease.

Fabric elements C. of the lake have high regenerator ability, especially an epithelium of a small bowel, to-ry at the person completely is replaced within 5 — 6 days.

Postmortem changes in S. of the lake arise rather quickly. Before everything there comes the autolysis in S. of the lake of a small bowel, later in S. of the lakes covered with a multilayer flat epithelium. At electronic microscopic examination reveal amotio of fibers of enterocytes from a basal membrane the first minutes after approach of death. By data A. I. Lysenko (1981), in 1/2 hours after death of a mitochondrion become condensed (with the condensed matrix and expanded mezhkristny spaces), in 2 hours they are exposed to swelling, in 3 hours generation of energy in the form of ATP completely disappears and sharply the maintenance of ADF and AMF decreases, the aerobic pathway is oppressed.

Pathology By the village of the lake it is described in articles about bodies (e.g., Throat ; Stomach , Intestines ; Uterus ; Bladder ; Roth, oral cavity ; Rectum etc.), and also in separate articles (e.g., Bronchitis , Gastritis , Duodenitis , Colitis etc.).

Bibliography: See bibliogr. to St. Stomach , Gall bladder , Intestines , Bladder , Gullet .

Yu. K. Yelets.