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The mucosal immune system consists of a cellular component, humoral immunity, and defense mechanisms that prevent the invasion of microorganisms and harmful foreign substances into the body. These defense mechanisms can be divided into physical barriers ( epithelial lining , mucus , cilia function , intestinal peristalsis , etc.) and chemical ...
A major digestive organ is the stomach. Within its mucosa are millions of embedded gastric glands. Their secretions are vital to the functioning of the organ. Most of the digestion of food takes place in the small intestine which is the longest part of the GI tract. The largest part of the GI tract is the colon or large intestine.
The gut-associated lymphoid tissue lies throughout the intestine, covering an area of approximately 260–300 m 2. [5] In order to increase the surface area for absorption, the intestinal mucosa is made up of finger-like projections (), covered by a monolayer of epithelial cells, which separates the GALT from the lumen intestine and its contents.
The gastrointestinal wall of the gastrointestinal tract is made up of four layers of specialised tissue. From the inner cavity of the gut (the lumen) outwards, these are the mucosa, the submucosa, the muscular layer and the serosa or adventitia. The mucosa is the innermost layer of the gastrointestinal tract.
identify and remove foreign substances present in organs, tissues, blood and lymph, by specialized white blood cells activate the adaptive immune system through antigen presentation act as a physical and chemical barrier to infectious agents; via physical measures such as skin and mucus, and chemical measures such as clotting factors and host ...
[13] [14] In the stomach, gastric acid serves as a chemical defense against ingested pathogens. [15] Within the genitourinary and gastrointestinal tracts, commensal flora serve as biological barriers by competing with pathogenic bacteria for food and space and, in some cases, changing the conditions in their environment, such as pH or available ...
Diagram of the alkaline mucous layer in the stomach with mucosal defense mechanisms. The gastric mucosa is the mucous membrane layer of the stomach, which contains the gastric pits, to which the gastric glands empty. In humans, it is about one mm thick, and its surface is smooth, soft, and velvety.
The mucosa-associated lymphoid tissue (MALT), also called mucosa-associated lymphatic tissue, is a diffuse system of small concentrations of lymphoid tissue found in various submucosal membrane sites of the body, such as the gastrointestinal tract, nasopharynx, thyroid, breast, lung, salivary glands, eye, and skin.