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==Pathophysiology==
 
==Pathophysiology==
 
====Anatomy====
 
====Anatomy====
In the horse, the squamous mucosa covers the lining of the oesophagus and about one third of the gastric wall.  It provides a protective barrier comprising a tightly bound superifcial layer of cornified cells.(EGUC)  This squamous epithelium has no absorptive or secretory function.  The glandular region of the stomach contains mucus-secreting cells and gastric glands.  The ''margo plicatus'' is analagous to the gastro-oesophageal junction in man, however it lacks the lower oesophageal sphincter that helps to prevent acidic injury of the squamous mucosa(Sanchez).  Equine gastric ulcers occur in the squamous portion of the stomach in 75-80% of cases.  The predilection sites in various groups are:
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In the horse, the squamous mucosa covers the lining of the oesophagus and about one third of the gastric wall.  It provides a protective barrier comprising a tightly bound superifcial layer of cornified cells.(EGUC)  This squamous epithelium has no absorptive or secretory function.  The glandular region of the stomach contains mucus-secreting cells and gastric glands.  The ''margo plicatus'' is analagous to the gastro-oesophageal junction in man, however it lacks the lower oesophageal sphincter that helps to prevent acidic injury of the squamous mucosa(Sanchez).  Equine gastric ulcers largely occur in the squamous region of the stomach.  The predilection sites in various groups are:
Adults: squamous epithelium, partcualry adjacent ot margo plicatus, glandular and antral invoevemnt increasing (9, 23 in Sanchez), severe cases can extend dorsally into squmous fundus (Sanchez)
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*Neonatal foals: glandular mucosa
Neonatal foals: glandular mucosa
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*Healthy suckling foals younger than 50 days: squamous mucosa adjacent to ''margo plicatus'' along the greater curvature, squamous epithelial desquamation
Healthy suckling foals younger than 50 days: squamous mucosa adjacent to margo plicatus along greetr curvature, squamous epithelial desquamation
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*Suckling foals with older than 50 days with clinical signs: squamous mucosa along lesser curvature, squamous mucosa of fundus and adjacent to ''margo plicatus''.
Sick suckling foals older than 50 days: squamous mucosa along lesser curvature, squamous mucosa of fundus and adjacent to margo plicatus.
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*Sucklers and early weaners: gastroduodenal ulcer disease (GDUD) – lesions in proximal duodenum, also severe lesions in squamous or glandular region
Sucklers and early weaners: GDUD – lesions in proximal duodenum, also severe lesions in squamous or g;landuar region
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*Adults: squamous epithelium, particularly adjacent to ''margo plicatus'', glandular and antral involvement becoming more common (9, 23 in Sanchez), severe cases of ulceration can extend dorsally into squamous fundus (Sanchez)
    
==Risk Factors==
 
==Risk Factors==
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