Gastrointestinal Physiology: An Introduction

Importance of the Gastrointestinal (GI) System in Veterinary Practice

• The GI system is crucial in both small and large animal medicine.

• For horses, it is considered the second most important system, often surpassed only by the limbs (colic and lameness being major concerns).

Clinical Cases Demonstrating GI System Importance

Case 1: Gastritis

• Definition: Inflammation of the stomach (gastric = stomach, -itis = inflammation).

• Occurrence: Frequently observed in both small and large animal practices.

• Endoscopic View: An endoscopic image of a canine patient's stomach shows:

  • Blue arrow: Points to a red, inflamed area, indicating abnormality.

  • White arrow: Points to normal, pinkish tissue.

Case 2: Gastric Ulcers in Equine Patients

• Prevalence: Especially significant in equine practice, making up approximately $90\%$ of a veterinarian's income from scoping racehorses and accounting for about $75\%$ of equine cases.

• Anatomy: The equine stomach has a myodophilus – a brownish tissue that separates the glandular and non-glandular regions.

• Pathology: Endoscopic views of affected stomachs show erosions and a yellowish discoloration, characteristic of gastric ulcers.

• Etiology: Horses, particularly racehorses, are highly competitive animals, which contributes to stress and ulcer formation (analogous to human stress for academic achievement like a $4.0$ GPA).

Case 3: Displacement of the Abomasum in Food Animals

• Affected Animals: Common in ruminants like cows, buffalo, goats, and sheep.

• Condition: Involves the displacement of the abomasum (one of the four stomach compartments) from its normal position (typically on the left side of the abdominal cavity) to the right side or becoming elevated.

  • Forms: Left Displacement of Abomasum (LDA) or Right Displacement of Abomasum (RDA).

• Abomasum Function: Often called the