Mucosa

Synonym: Mucosa, Tunica mucosa

Definition

The word “mucous membrane” was translated directly from the Latin “tunica mucosa”. “Tunica” means skin, tissue and “mucosa” comes from “mucus” mucus. The mucosa is a protective layer that lines the inside of hollow organs such as the lungs or stomach. It has a slightly different structure than normal skin and has no horny layer and no hairs. As the name suggests, this epithelial (=skin) layer is responsible for the production of mucus.

Structure of the mucosa

As mentioned, the mucous membrane is unkeratinized, one- (e.g. in the intestine) or multi-layered (as in the oral cavity) and can be flat in shape or have an elongated, slender basic form that is higher than broad. The three-layer structure is basically the same in all mucous membranes: the innermost layer facing the cavity is the lamina epithelialis mucosae. It is the actual epithelial layer.

The tissue layer of loose connective tissue and other fibers lies on top of it from the outside. It is called Lamina propria mucosae. The Lamina muscularis mucosae, which consists of a delicate layer of smooth muscle cells, is attached to the outside of the epithelium.

To enlarge the surface, so-called microvilli (finger-shaped protuberances), but also cincilia (cilia) or stereocilia are formed. The larger the surface, the more nutrients the mucosa can absorb or exchange. The mucous membrane usually contains glands that form mucus (mucous substances) and thus keep the tunica mucosa moist. However, there are also mucous membranes, such as the vaginal mucosa, which is glandless. Here the production of mucus is taken over by adjacent sections.

Function of the mucosa

The mucosa renews itself quite quickly, approximately every 3-6 days. It has a certain barrier function and thus serves as a mechanical demarcation of the organ surface. Furthermore, the mucosa takes over secretion and resorption processes by transporting molecules into or out of the mucosa with the help of active transport proteins.

In addition, the tunica mucosa has lymph follicles, which contain the “mucosa associated lymphoid tissue” or MALT. They are able to produce certain immunoglobulins, especially a lot of IgA, and protect themselves against invading pathogens that cause illness. This defense mechanism should be maintained by a regular intake of micronutrients through food and can be reduced by factors such as stress, environmental pollution (heavy metals, smoking, alcohol, pesticides), medication, insufficient sleep, etc.

Consequently, allergies (hay fever, asthma) as well as bacterial gastritis or cystitis and also viral mucous membrane diseases (rhinitis and bronchitis) can occur. Chronic inflammation can lead to thickening of the tunica mucosa, but can also cause other symptoms such as belching, heartburn, diarrhea, bleeding, etc. (for example, in chronic inflammation of the mucous membranes of the stomach and intestines).

Often an operative measure is the result. In order to avoid this, it is necessary to supply the important nutrients through food on a daily basis and to avoid bad factors such as stress, smoking, bacterial or viral infection, etc. or to treat them as soon as possible.