Gastrointestinal Physiology – BCSE Study Guide

Overview and Clinical Importance

Gastrointestinal (GI) physiology encompasses the coordinated functions of motility, secretion, digestion, and absorption that convert ingested food into absorbable nutrients. Understanding GI physiology is essential for veterinarians because digestive disorders are among the most common presentations across all species.

This topic spans multiple BCSE domains including Physiology (Domain 2), Medicine (Domain 4), and Surgery (Domain 6). Questions frequently test your understanding of species differences, particularly comparing monogastric digestion with ruminant forestomach fermentation and hindgut fermentation in horses and rabbits.

Section 1: GI Motility Patterns

GI motility is essential for mixing food with digestive secretions, propelling contents through the tract, and regulating transit time. Motility is controlled by the enteric nervous system (ENS), often called the "second brain," along with hormonal and local factors.