University of Tennessee College of Veterinary Medicine – Horse Owner Seminar Benjamin R Buchanan, DVM Resident Large Animal Internal Medicine Resident Veterinary Emergency and Critical Care

Guide to the Equine Gut Normal Equine Gastrointestinal Anatomy

Divisions Oral Cavity Oral Cavity Esophagus Esophagus Small Intestine Small Intestine Proximal Proximal Mid Mid Distal Distal Cecum Cecum Large Colon Large Colon Transverse Colon Small Colon Rectum

Oral Cavity

Pharynx and Guttural Pouch Pharynx and Guttural Pouch Pharynx Pharynx Epiglottis Epiglottis Arytenoids Arytenoids Opening to Esophagus Opening to Esophagus GP GP Nerves control swalloing Nerves control swalloing

Esophagus Connects oral cavity to stomach Connects oral cavity to stomach Valve where it travels from thorax into stomach Valve where it travels from thorax into stomach Swallowing unconsciously controlled Swallowing unconsciously controlled Covered by squamous tissue Covered by squamous tissue

Mesentery Long sheet of tissue Long sheet of tissue Connects intestines to body wall Connects intestines to body wall Carries blood vessels and nerves Carries blood vessels and nerves

Stomach Covered by two types of tissue Covered by two types of tissue Squamous tissue Squamous tissue Mucosal tissue Mucosal tissue Anchored in the cranial left abdomen Anchored in the cranial left abdomen Digestion of food material Digestion of food material

Small Intestine Proximal Proximal Duodenum Duodenum Connection for liver and pancreas Connection for liver and pancreas Digestion of food material Digestion of food material Short mesentery Short mesentery Mid Mid Jejunum Jejunum Digestion and absorption Digestion and absorption Long mesentery Long mesentery

Small Intestine Distal Distal Ileum Ileum Controls rate of flow into cecum/colon Controls rate of flow into cecum/colon Tape worms Tape worms Short mesentery Short mesentery

Cecum Appendix Appendix Fermentation and fiber digestion Fermentation and fiber digestion Base and apex Base and apex 8-10 gallons fluid and gas 8-10 gallons fluid and gas Anchored at base by mesentery Anchored at base by mesentery

Large Colon Modification of ascending colon Modification of ascending colon Travels from right flank to liver to left flank back to liver back to right flank Travels from right flank to liver to left flank back to liver back to right flank Anchored on right by short mesentery, free on left Anchored on right by short mesentery, free on left Ferementation and fiber digestion Ferementation and fiber digestion

Transverse Colon Short connection of large colon to small colon Short connection of large colon to small colon Short mesentery Short mesentery

Small Colon Descending colon Descending colon Water reabsorption Water reabsorption Fecal storage Fecal storage Long mesentery Long mesentery

Rectum Abdominal and extraabdominal Abdominal and extraabdominal Short mesentary Short mesentary Fecal storage Fecal storage Route for abdominal palpation Route for abdominal palpation

Glass Horse

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