GI: 334 - 336 Flashcards
What defines the foregut?
Pharynx to duodenum
What defines the midgut?
Duodenum to proximal 2/3 of transverse colon
What defines the hindgut?
Distal 1/3 of transverse colon to anal canal above the pectinate line
What 3 things that lead to developmental defects of the anterior abdominal wall and what are their associated defects?
- Failure of rostral fold close - sternal defects
- Failure of lateral folds to close - omphalocele, gastroschisis
- Failure of caudal folds to close - bladder exstrophy
What is duodenal atresia due to?
Failure to recanalize
What is duodenal atresia associated with?
Trisomy 21
What causes jejunal, ileal, colonic atresia?
Vascular accident
Explain the two important steps in midgut development.
- Week 6: Midgut herniates through umbilical ring
2. Week 10: Returns to abdominal cavity and rotates around SMA
What is gastroschisis?
Extrusion of abdominal contents through abdominal folds, not covered by peritoneum
What is omphalocele?
Persistence of herniation of abdominal contents into umbilical cord, covered by peritoneum
How does TE fistula typically present?
Drooling, choking, and vomiting with first feeding
What would you see on CXR with a TE fistula?
Air in the stomach
What is a clinical test for TE fistula?
Failure to pass nasogastric tube into stomach
What causes cyanosis in TE fistula?
Laryngospasms which work to avoid reflux-related aspiration
What causes congenital pyloric stenosis?
Hypertrophy (of the pylorus)
How does congenital pyloric stenosis present?
Palpable “olive” mass in epigastric region and nonbilious projectile vomiting at 2-6 weeks
What is the treatment for congenital pyloric stenosis?
Surgical incision
How common is congenital pyloric stenosis?
1/600 live births
Congenital pyloric stenosis is more common in what subset of patients?
Firstborn males
What are the different embryological precursors to the pancreas?
Pancreas comes from the foregut
Ventral pancreatic buds - form pancreatic head, main pancreatic duct, uncinate process
Dorsal bud - forms body, tail, isthmus, accessory pancreatic duct
What are two developmental defects that can occur with the pancreas?
- Annular pancreas
2. Pancreas divisum
What happens in an annular pancreas?
Ventral pancreatic bud abnormally encircles 2nd part of the duodenum, forms a ring of pancreatic tissue that may cause duodenal narrowing
What happens in pancreas divisum?
Ventral and dorsal parts fail to fuse at 8 weeks
What does the spleen vs. its blood supply arise from embryologically?
Spleen - mesentery of the stomach (mesodermal)
Blood supply - from the foregut (celiac artery)
What can injury to retroperitoneal structures lead to?
Blood or gas accumulation in retroperitoneal spaces
What are the retroperitoneal structures?
Mnemonic: SAD PUCKER
Suprarenal (adrenal) glands
Aorta and IVC
Duodenum (2nd through 4th parts)
Pancreas (except tail) Ureters Colon (descending and ascending) Kidneys Esophagus (lower 2/3) Rectum (partially)
What are 6 important GI ligaments?
- Falciform
- Hepatoduodenal
- Gastrohepatic
- Gastrocolic
- Gastrosplenic
- Splenorenal
What does the falciform ligament connect?
Liver to the anterior abdominal wall
What is contained within the falciform ligament?
Ligamentum teres hepatis (derivative of fetal umbilical vein)
What does the hepatoduodenal ligament connect?
Liver to duodenum
What does the hepatoduodenal ligament contain?
Portal triad: proper hepatic artery, portal vein, common bile duct
What does the gastrohepatic ligament connect?
Liver to less curvature of the stomach
What does the gastrohepatic ligament contain?
Gastric arteries
What does the gastrocolic ligament connect?
Greater curvature of stomach and transverse colon
What does the gastrocolic ligament contain?
Gastroepiploic arteries
What does the gastrosplenic ligament connect?
Greater curvature of stomach and spleen
What does the gastrosplenic ligament contain?
Short gastrics, left gastroepiploic vessels
What does the splenorenal ligament connect?
Spleen to posterior abdominal wall
What does the splenorenal ligament contain?
Splenic artery and vein, tail of pancreas
Which ligament separates the greater and lesser sacs on the right and why is this important?
Gastrohepatic - may be cut during surgery to access the lesser sac
What is the Pringle maneuver?
Ligament may be compressed between thumb and index finger placed in omental foramen to control bleeding
What separates the greater and lesser sacs on the left?
Gastrosplenic
Which ligament is part of the greater omentum?
Gastrocolic ligament
