Difference between revisions of "Stomach and Abomasum - Pathology"
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| + | ==Introduction to the Stomach and Abomasum== | ||
| + | * In most animals, after swallowing, food leaves the [[Oesophagus - Anatomy & Physiology|oesophagus]] and enters the [[Forestomach - Anatomy & Physiology|stomach]]. In ruminants, food enters the [[The Abomasum|abomasum]] after fermentation in the forestomach. | ||
| + | * The [[Forestomach - Anatomy & Physiology|stomach]] acts as a reservoir in which a semi-solid mass (chyme) is formed from the ingested food before passing into the [[Duodenum - Anatomy & Physiology|duodenum]]. | ||
| + | * With the exception of water, little absorption occurs in the [[Forestomach - Anatomy & Physiology|stomach]]. | ||
| + | * Gastric juice is highly acidic, and contains: | ||
| + | ** HCl, produced by the parietal cells | ||
| + | *** Maintains gastric pH at 2, which denatures protein. | ||
| + | ** Pepsin, derived from pepsinogen, produced by zymogen cells | ||
| + | *** The action of HCl facilitates this. | ||
| + | * Surface epithelial cells and mucous neck cells produce mucus which forms an alkaline sheet over the epithelial surface. | ||
| + | ** Provides protection from the gastric juice. | ||
| + | * The cells of the mucosa are renewed at different rates. This is an important considerination in the pathogenesis of certain gastric diseases. | ||
| + | ** Surface epithelial cells and mucous neck cells are replaced about every 3 days. | ||
| + | ** Parietal cells and zymogen cells are produced at a slower rate; the parietal cells have a half-life of 23 days. | ||
| + | ===Defence Mechanisms=== | ||
| + | # Secretions : | ||
| + | #* Mucus (inhibits contact with mucosa, protects surface). | ||
| + | #* Acid (parietal cells) | ||
| + | #* Digestive enzymes (pepsin from gastric chief cells) | ||
| + | # Epithelium: | ||
| + | #* Provides a barrier | ||
| + | #** Stratified squamous epithelium; multilayered, high cell turnover | ||
| + | # Movement: | ||
| + | #* Continuous movement discourages persistence of insult at mucosa. | ||
| + | ===Miscellaneous=== | ||
| + | *[[Stomach - comparative anatomy|Camelid Stomach]] | ||
| + | ==Stomach and Abomasum - Contents== | ||
| + | ===[[Stomach and Abomasum Inflammation - Pathology|Inflammatory Conditions]]=== | ||
| + | ===[[Stomach and Abomasum Proliferative - Pathology|Proliferative Pathology]]=== | ||
| + | ===[[Stomach and Abomasum Parasites - Pathology|Parasites]]=== | ||
| + | ===[[Stomach and Abomasum Physical Disruptions - Pathology|Physical Disruptions]]=== | ||
| + | ===[[Stomach and Abomasum Toxicology - Pathology|Toxicology]]=== | ||
| + | ===[[Stomach and Abomasum Consequences of Gastric Disease - Pathology|Consequences of Gastric Disease]]=== | ||
| + | =oLD= | ||
| + | ===Miscellaneous=== | ||
| + | *[[Stomach - comparative anatomy|Camelid Stomach]] | ||
| + | ==Stomach and Abomasum - Contents== | ||
| + | ===[[Stomach and Abomasum - Inflammation|Inflammatory Conditions]]=== | ||
| + | ===[[Stomach and Abomasum - Proliferative Pathology|Proliferative Pathology]]=== | ||
| + | ===[[Stomach and Abomasum - Parasites|Parasites]]=== | ||
| + | ===[[Stomach and Abomasum - Physical Disruptions|Physical Disruptions]]=== | ||
| + | ===[[Stomach and Abomasum - Toxicology|Toxicology]]=== | ||
| + | ===[[Stomach and Abomasum - Consequences of Gastric Disease|Consequences of Gastric Disease]]=== | ||
Revision as of 22:59, 25 August 2008
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Introduction to the Stomach and Abomasum
- In most animals, after swallowing, food leaves the oesophagus and enters the stomach. In ruminants, food enters the abomasum after fermentation in the forestomach.
- The stomach acts as a reservoir in which a semi-solid mass (chyme) is formed from the ingested food before passing into the duodenum.
- With the exception of water, little absorption occurs in the stomach.
- Gastric juice is highly acidic, and contains:
- HCl, produced by the parietal cells
- Maintains gastric pH at 2, which denatures protein.
- Pepsin, derived from pepsinogen, produced by zymogen cells
- The action of HCl facilitates this.
- HCl, produced by the parietal cells
- Surface epithelial cells and mucous neck cells produce mucus which forms an alkaline sheet over the epithelial surface.
- Provides protection from the gastric juice.
- The cells of the mucosa are renewed at different rates. This is an important considerination in the pathogenesis of certain gastric diseases.
- Surface epithelial cells and mucous neck cells are replaced about every 3 days.
- Parietal cells and zymogen cells are produced at a slower rate; the parietal cells have a half-life of 23 days.
Defence Mechanisms
- Secretions :
- Mucus (inhibits contact with mucosa, protects surface).
- Acid (parietal cells)
- Digestive enzymes (pepsin from gastric chief cells)
- Epithelium:
- Provides a barrier
- Stratified squamous epithelium; multilayered, high cell turnover
- Provides a barrier
- Movement:
- Continuous movement discourages persistence of insult at mucosa.