Changes

*'''Mucus:''' secreted by specialised mucous neck cells.  A viscous, hydrophobic glycoproteinaceous gel that adheres to the mucosa and resists acid and pepsin contact. Also acts as a lubricant to minimise mechanical damage.(EGUC)

*'''Mucus:''' secreted by specialised mucous neck cells.  A viscous, hydrophobic glycoproteinaceous gel that adheres to the mucosa and resists acid and pepsin contact. Also acts as a lubricant to minimise mechanical damage.(EGUC)

*'''Bicarbonate:''' secreted by gastric mucosal cells.  Secretion triggered by luminal acid concentrations, mechanical irritation, and release of endogenous prostaglandins. Bicarbonate trapped in the mucous layer forms a pH gradient allowing a physiological pH at the mucosal surface and a gastric acid pH at the luminal surface.(EGUC)

*'''Bicarbonate:''' secreted by gastric mucosal cells.  Secretion triggered by luminal acid concentrations, mechanical irritation, and release of endogenous prostaglandins. Bicarbonate trapped in the mucous layer forms a pH gradient allowing a physiological pH at the mucosal surface and a gastric acid pH at the luminal surface.(EGUC)

*'''Epidermal growth factors:''' found in salivary gland secretions, promote DNA synthesis and proliferation of gastric mucosal cells. Also play a role in prostaglandin synthesis. PGE2 is involved in:

*'''Epidermal growth factors:''' found in salivary gland secretions, promote DNA synthesis and proliferation of gastric mucosal cells. Also play a role in prostaglandin synthesis and inhibit HCl secretion by the parietal glands.(EGUC)

Suppression of HC1 secretion  

*'''Epithelial restitution mechanisms:''' important in the maintenance of gastric mucosal integrity (maintain tight junctions). Epithelial injury induces migration of adjacent cells to replace damaged cells within minutes without the need of new cell proliferation.  Shear forces, induced by mixing of ingested material, are counteracted by epithlial restoration.(EGUC)

*'''Adequate mucosal blood supply:''' required to provide the mucosa with oxygen and nutrients to produce the mucus-bicarbonate layer and to support rapid turnover of epithelial cells.  Also required to remove acid that has diffused through the mucous layer to the mucosa.(EGUC)

*'''Prostaglandins:''' inhibit acid secretion, promote mucosal blood flow (through vasodilation), increase mucus and bicarbonate secretions and support mucosal cell repair.  PGE2 is especially important in these functions.(EGUC)

Epithelial restitution mechanisms (maintain tight junctions) Epithelial cell restitution is another important mechanism in the maintenance of gastric mucosal integrity. Epithelial cells act as a protective covering, counter shear forces that induce damage, and provide rapid restoration of damaged protective barriers. In the case of the gastric mucosa, epithelial injury induces a migration of adjacent cells to replace damaged cells. This occurs within minutes without need of new cell proliferation. Shear forces, induced by mixing of ingested material raking against the mucosal wall, cause cell damage that is normally countered by the process of epithelial restoration.

=====Other intrinsic defence mechanisms=====

'''Gastrodudodenal motility'''

 

In the nonglandular region, intercellular tight junctions and intracellular buffering systems act as barriers, while the  Adequate mucosal blood flow and mucus secretion is maintained by appropriate prostaglandin release (Morrissey et al. 2008).  Epidermal growth factor has also been found to contribute to the healthy maintenance and repair of equine gastric squamous epithelium (Jeffrey et al. 2001). (Martineau 2009) Gastrodudodenal motility.

 

 

==Risk Factors==

==Risk Factors==