Mucous membrane

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Schematic cross section through the intestine
Cross section through the mucous membrane of the esophagus :
g: Lamina epithelialis mucosae
f: Lamina propria mucosae
e: Lamina muscularis mucosae (belongs to the lamina propria)

The mucous membrane , in medical nomenclature tunica mucosa (from the Latin tunica “skin, tissue (layer)” and mucus , “ mucus ”) or mucosa for short , is the name given to the protective layer that lines the interior of hollow organs . The conjunctiva of the eye , the inside of the penis foreskin and the covering layer of the glans and the clitoris are also mucous membranes. In contrast to the external skin , it has no horny layer and no hair . The production of mucous substances, the mucins, is essential (and eponymous) for mucous membranes .


A mucous membrane consists of an epithelial layer ( lamina epithelialis mucosae ), an epithelial muscle layer ( lamina muscularis mucosae ) and an intermediate layer of connective tissue ( lamina propria mucosae ).

The epithelium can be single-layered (e.g. intestine ) or multilayered (e.g. oral cavity ). In some organs, the epithelium can also show a specific keratinization on the surface (e.g. fore stomachs of ruminants ). Surface enlargements in the form of microvilli , sometimes also kinocilia and stereocilia, are often found on the epithelial cells .

The own layer mostly contains glands ( glandular mucous membrane) that keep the mucous membrane moist. However, it can also be glandless (so-called cutaneous mucous membrane , e.g. vagina ), where the fluid released by the epithelium and / or the glandular secretions of adjacent sections take over the formation of the fluid film. Only in the area of ​​the gastrointestinal tract is a narrow muscle layer, the lamina muscularis mucosae, embedded in the intrinsic layer . While the term “mucous membrane” is also generally used for glandeless linings of internal organs in animal anatomy, this is not used uniformly in the human anatomical literature. Some authors dispense with a generic term for epithelium and lamina propria in the case of glandless structures.


Buccal buccal mucosa

Mucous membranes serve to mechanically delimit the organ surface. Many mucous membranes have the property of using active transport proteins (e.g. glucose transporters ) on the surface of the mucous membrane to transport molecules in a specific direction, thus enabling both secretion and absorption processes . Lymph nodes are often found in the self- layer . Mucous membranes can secrete immunoglobulins (especially IgA) and thus have an important protective function against invading pathogens. These by the "mucosal-associated lymphoid tissue" or MALT (of English. M ucosa a ssociated l ymphoid t issue ) and mediated by IgA realized specific defense against infection is also called mucosal immunity (engl .: mucosal immunity hereinafter).



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Wiktionary: mucous membrane  - explanations of meanings, word origins, synonyms, translations