Flashcards in EXAM #1: EMBRYOLOGY OF THE GI SYSTEM Deck (54)
What germ layer do the stomodeum and protodeum develop from?
What are the derivatives of the foregut?
Pharynx to duodenum distal to the bile duct, plus:
- Biliary apparatus
- Respiratory system
What artery supplies the foregut?
What are the midgut derivatives?
Duodenum distal to the bile duct to the right half of the transverse colon
What artery supplies the midgut?
What are the derivatives of the Hindgut?
Distal half of the transverse colon to the superior part of anal canal, plus:
- Bladder epithelium
- Most of the urethra
What artery supplies the Hindgut?
What part of the primitive gut does the respiratory system develop from?
Describe the normal development of the esophagus.
1) Single tube
2) Branching of a lung bud and foregut from common tuve
3) Trachea and respiratory passageway are separted by tracheoesophageal folds that form a septum
4) Esophagus elongates
****Note that growth of the epithelium in the lumen of the esophagus nearly obstructs the esophagus and then re-canalizes****
What is a Short Esophagus?
Failure of the esophagus to elongate pulls some of the stomach into the thoracic cavity that can lead to lung hypoplasia
What is esophageal atresia?
Failure of the esophagus to form
What is tracheoesophageal fistula?
- Proximal esophageal atresia
- Fistula forms between trachea and distal esophageal segment
What is esophageal stenosis?
Narrowing of the esophageal lumen
What are the three mechanisms that cause esophageal stenosis?
1) Sequestration of respiratory tissue elements
2) Myenteric plexus damage that causes hypertrophy (muscularis mucosa)
3) Mucosal diaphragm
What vascular anomaly can lead to esophageal stenosis?
4th branch on the LEFT side of the aortic arch; an anomalous right subclavian retroesophageal artery
What is the eponym for an anomalous right subclavian retroesophageal artery?
Describe the normal development of the stomach.
1) Expansion of primitive gut tube
2) More dorsal growth than ventral
3) 90 degree CLOCKWISE rotation
4) Slight pivot from growing esophagus
What part of the primitive stomach becomes the greater curvature?
What part of the primitive stomach becomes the lesser curvature?
What is the LARP mnemonic?
What is Infantile Hypertrophic Pyloric Stenosis?
Hypertrophy of the pyloric sphincter in the neonate
What is the US characteristic that is pathognomonic for an Infantile Hypertrophic Pyloric Stenosis?
What is the hallmark sign of Infantile Hypertrophic Pyloric Stenosis?
Non-bilious projectile vomiting
What causes duodenal stenosis?
Incomplete recanalization of the duodenum
What causes duodenal atresia?
Complete failure of recanalization
Mutations in what growth factor have been implicated in duodenal obstruction?
Sonic Hedge Hog
What x-ray findings is pathogmnemonic for duodenal atresia?
Double Bubble Sign
What is the most common cause of jejunal and ileal atresia?
Vascular accident, NOT failure of recanalization
What are the three stages of midgut rotation? What happens during these stages?
1) Herniation into the umbilical cord
2) Reduction back into the abdominal cavity
3) Fixation to posterior abdominal wall