Embryo of the GI Tract Flashcards
(42 cards)
Time frame for development of the GI tract
4th to 10th weeks
Txn factor for the esophagus
For the duodenum and pancreas
For the SI
For the LI
SOX2
PDX1
CDXC
CDXA
The development of the GI tract requires the communication between what two embryonic layers?
Endoderm (epithelium) and splanchnic mesoderm (mesenchyme)
How might epithelium cause an atresia in the gut tube?
Temporarily occludes it, but then never re-canalizes
Where is the oblique muscle layer when it is included in the GI wall?
Innermost, just after the submucosa
The mesentery is made from what layer?
Parietal peritoneum (splanchnic mesoderm)
Where is the only place where ventral mesentery can be seen in an adult?
Falciform ligament and lesser omentum
Innervation of the foregut
Spinal roots
Greater splanchnic n. and celiac plexus
T5-9
Innervation of the midgut
Spinal nerve roots
Lesser splanchnic n. and superior mesenteric plexus
T9-12
Innervation of the hindgut
Spinal nerve roots
Least splanchnic n. and inferior mesenteric plexus
T12-L2
In the pathway of sympathetic innervation, the “prevertebral ganglia” that the splanchnic nn. go to after leaving the abdominal sympathetic trunk are where?
Celiac, SM, and IM plexuses
Parasympathetic innervation of foregut
Midgut?
Vagus n.
SAME
Parasympathetic innervation of hindgut (w/ levels)
Pelvic splanchnic nn. (S2-4)
If urine is leaking from an umbilicus, what is the problem?
Patent allantois (to become the urachus)
If feces is leaking from an umbilicus, what is the problem?
Patent vitelline duct (to be Meckel’s diverticulum)
3 Tx’s for a double tracheoesophageal fistula
What is crucial to these?
Colon interposition
Gastric tube esophagoplasty
Gastric transposition
MUST KEEP BLOOD SUPPLY IN TACT
Esophageal diverticulum
Blind benign pouch off the side of the esophagus that could collect food/liquid
Why does the stomach turn?
Posterior grows faster than anterior, so needs more space to keep growing
If, 2-3 weeks after birth, a baby is vomiting NON-GREEN stuff after feeding, what is most likely the problem?
What can sometimes be seen externally?
Hypertrophic pyloric stenosis
Bloated stomach and/or duodenum poking through ant. abd. wall
Double bubble sign
2 bloated areas on x-ray (stomach and duodenum) due to a duodenal atresia (occlusion)
What organs develop in the ventral mesentery?
Liver and gall bladder
Stomach and part of duodenum
Why are there often 2 duodenal papillas?
B/c ventral and dorsal “buds” of pancreas were both connected until they fused
What 2 areas signal the liver to develop in the right place?
Where does it end up coming from?
Heart and septum transversum
Posterior endoderm
Why does the lesser sac become so small?
The liver grows into the right “sac” and fills it in