Difference between revisions of "Stomach and Abomasum - Pathology"

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#REDIRECT[[:Category:Stomach and Abomasum - Pathology]]
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|backcolour =BCED91
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|linkpage =Alimentary System - Pathology
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|linktext =Alimentary System
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|maplink = Alimentary System (Content Map) - Pathology
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|pagetype =Pathology
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==Introduction to the Stomach and Abomasum==
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* 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.
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* 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]].
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* With the exception of water, little absorption occurs in the [[Forestomach - Anatomy & Physiology|stomach]].
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* Gastric juice is highly acidic, and contains:
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** HCl, produced by the parietal cells
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*** Maintains gastric pH at 2, which denatures protein.
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** Pepsin, derived from pepsinogen, produced by zymogen cells
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*** The action of HCl facilitates this.
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* Surface epithelial cells and mucous neck cells produce mucus which forms an alkaline sheet over the epithelial surface.
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** Provides protection from the gastric juice.
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* The cells of the mucosa are renewed at different rates. This is an important considerination in the pathogenesis of certain gastric diseases.
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** Surface epithelial cells and mucous neck cells are replaced about every 3 days.
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** Parietal cells and zymogen cells are produced at a slower rate; the parietal cells have a half-life of 23 days.
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===Defence Mechanisms===
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# Secretions :
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#* Mucus (inhibits contact with mucosa, protects surface).
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#* Acid (parietal cells)
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#* Digestive enzymes (pepsin from gastric chief cells)
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# Epithelium:
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#* Provides a barrier
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#** Stratified squamous epithelium; multilayered, high cell turnover
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# Movement:
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#* Continuous movement discourages persistence of insult at mucosa.
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===[[Stomach and Abomasum Inflammation - Pathology|Inflammatory Conditions]]===
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===[[Stomach and Abomasum Proliferative - Pathology|Proliferative Pathology]]===
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===[[Stomach and Abomasum Parasites - Pathology|Parasites]]===
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===[[Stomach and Abomasum Physical Disruptions - Pathology|Physical Disruptions]]===
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===[[Stomach and Abomasum Toxicology - Pathology|Toxicology]]===
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===[[Stomach and Abomasum Consequences of Gastric Disease - Pathology|Consequences of Gastric Disease]]===

Revision as of 23:10, 25 August 2008

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()Map ALIMENTARY SYSTEM (Map)



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.
  • 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

  1. Secretions :
    • Mucus (inhibits contact with mucosa, protects surface).
    • Acid (parietal cells)
    • Digestive enzymes (pepsin from gastric chief cells)
  2. Epithelium:
    • Provides a barrier
      • Stratified squamous epithelium; multilayered, high cell turnover
  3. Movement:
    • Continuous movement discourages persistence of insult at mucosa.

Inflammatory Conditions

Proliferative Pathology

Parasites

Physical Disruptions

Toxicology

Consequences of Gastric Disease

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