Gastrointestinal/Nutrition

~8% of blueprint

Luminal GI, hepatobiliary, pancreatic, nutritional deficiencies.

Disease Profiles

Region: Right upper quadrant, hepatobiliary system.
Key Structures: Hepatic ducts → common hepatic duct + cystic duct → common bile duct → ampulla of Vater (with the pancreatic duct) → sphincter of Oddi.
Clinical Correlation: Cystic duct stone → cholecystitis; CBD stone → obstructive jaundice; ampullary stone → gallstone pancreatitis.

High-Yield Pearl

Charcot’s triad — RUQ pain, jaundice, fever — points to ascending cholangitis from CBD obstruction.

Region: Embryologic divisions of the abdominal GI tract.
Key Structures: Foregut → celiac trunk; Midgut → SMA; Hindgut → IMA.
Clinical Correlation: Visceral pain localizes by division: foregut = epigastric, midgut = periumbilical, hindgut = suprapubic.

High-Yield Pearl

Appendicitis starts periumbilical (midgut visceral pain), then localizes to the RLQ once the parietal peritoneum is involved.

Region: Throughout the gut tube.
Key Structures: Mucosa, submucosa (Meissner plexus), muscularis externa (Auerbach/myenteric plexus), serosa/adventitia.
Clinical Correlation: Depth of invasion stages GI cancers; absent myenteric & submucosal ganglia → Hirschsprung disease.

High-Yield Pearl

Myenteric (Auerbach) plexus drives motility; submucosal (Meissner) plexus drives secretion & blood flow.