GI tract
| Gut Segment | Extent / Boundaries | Key Derivatives | Arterial Supply | Innervation |
| Foregut | Oropharyngeal membrane - Duodenum (proximal to major duodenal papilla) | * Pharynx, lower respiratory tract * Esophagus, stomach * Proximal 1/2 of duodenum * Liver, gallbladder, biliary apparatus * Pancreas | Celiac Trunk | Parasympathetic: Vagus Nerve (CN X) |
| Midgut | Distal duodenum - Proximal 2/3 of transverse colon | * Distal 1/2 of duodenum * Jejunum & ileum * Cecum & appendix * Ascending colon * Proximal 2/3 of transverse colon | Superior Mesenteric Artery (SMA) | Parasympathetic: Vagus Nerve (CN X) |
| Hindgut | Distal 1/3 of transverse colon - Cloacal membrane | * Distal 1/3 of transverse colon * Descending & sigmoid colon * Rectum & upper anal canal (above pectinate line) * Epithelium of urinary bladder & urethra | Inferior Mesenteric Artery (IMA) | Parasympathetic: Pelvic Splanchnic Nerves (S2–S4) |