Gastric mucosal barrier
Encyclopedia
The gastric mucosal
barrier is the property of the stomach
that allows it to contain acid.
If the barrier is broken, as by acetylsalicylic acid (ASS, aspirin) in acid solution, acid diffuses back into the mucosa where it can cause damage to the stomach itself.
The barrier consists of three protective componentshttp://hmi.sinclair.edu/module_lesson.asp?ModuleID=10&LessonID=8. These provide the additional resistance for the mucosal surface of the stomach. The three components include:
Cells in the epithelium of the stomach are bound by tight junctions that repel harsh fluids that may injure the stomach lining.
The mucus covering is derived from mucus secreted by surface epithelial cells and mucosal neck cells. This insoluble mucus forms a protective gel-like coating over the entire surface of the gastric mucosa. The mucus protects the gastric mucosa from autodigestion by e.g. pepsin
and from erosion by acids and other caustic materials that are ingested.
The bicarbonate ions are secreted by the surface epithelial cells. The bicarbonate ions act to neutralize harsh acids.
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
barrier is the property of the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
that allows it to contain acid.
If the barrier is broken, as by acetylsalicylic acid (ASS, aspirin) in acid solution, acid diffuses back into the mucosa where it can cause damage to the stomach itself.
The barrier consists of three protective componentshttp://hmi.sinclair.edu/module_lesson.asp?ModuleID=10&LessonID=8. These provide the additional resistance for the mucosal surface of the stomach. The three components include:
- a compact epithelial cell lining
Cells in the epithelium of the stomach are bound by tight junctions that repel harsh fluids that may injure the stomach lining.
- a special mucus covering
The mucus covering is derived from mucus secreted by surface epithelial cells and mucosal neck cells. This insoluble mucus forms a protective gel-like coating over the entire surface of the gastric mucosa. The mucus protects the gastric mucosa from autodigestion by e.g. pepsin
Pepsin
Pepsin is an enzyme whose precursor form is released by the chief cells in the stomach and that degrades food proteins into peptides. It was discovered in 1836 by Theodor Schwann who also coined its name from the Greek word pepsis, meaning digestion...
and from erosion by acids and other caustic materials that are ingested.
- bicarbonateBicarbonateIn inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...
ions
The bicarbonate ions are secreted by the surface epithelial cells. The bicarbonate ions act to neutralize harsh acids.