Difference between revisions of "Stomach and Abomasum - Pathology"

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#REDIRECT[[:Category:Stomach and Abomasum - Pathology]]
 
 
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|maplink = Alimentary System (Content Map) - 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 - Anatomy & Physiology|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.
 
===[[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]]===
 

Latest revision as of 12:42, 29 May 2010