2. Gastric Mucosal Barrier
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, or any other factor, acid diffuses back into the mucosa where it can cause damage to the stomach itself.

3. Components Of Gastric Mucosal Barrier
A compact epithelial cell lining
A special mucous covering
Impermeability of luminal membrane of the gastric mucosal cells to hydrogen ions
Rapid replacement of entire stomach lining

4. 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.

5. Special Mucus Covering
Source:
The mucous covering is derived from mucous secreted by surface epithelial cells and mucosal neck cells.
This insoluble mucous forms a protective gel- like coating over the entire surface of the gastric mucosa.

6. Special Mucus Covering
Functions:
By virtue of its lubricating properties , mucous protects the gastric mucosa against mechanical injury
The mucus protects the gastric mucosa from autodigestion by e.g. pepsin and from erosion by acids and other materials that are ingested.
Being alkaline it helps protect against acid injury by neutralizing HCl, but does not interfere with its function.

7. Impermeability of luminal membrane of the gastric mucosal cells to hydrogen ions
Function: So that HCl present in stomach cannot penetrate into the cells to cause intracellular damage.

8. Rapid replacement of entire stomach lining
This further enhances the strength of gastric mucosal barrier.
Entire stomach lining is replaced every 3 days.
Because of rapid mucosal turnover , cells are replaced before they are exposed to the wear and tear of harsh gastric conditions long enough to suffer damage.