Digestive System Development I&II Flashcards
where does most of the GI derive from?
endoderm
what controls the regional differentiation?
sonic and indian hedgehog - SHH, IHH
intraperitoneal vs retroperitoneal surgery
intraperitoneal less invasive
- require less cutting
- faster recovery time
what happens with hypertrophy of the falciform ligament?
underdeveloped liver and will not have Barr area –> caught under diaphragm causing respiratory problems
effects of Doral mesentery problems?
cannot anchor stomach or develop greater omentum
blood supply of foregut?***
celiac trunk
what occurs with fast proliferation of epithelial cells of esophagus?
can narrow esophagus causing atresia or stenosis
stomach rotation
dorsal border grows faster to become greater curvature & rotates 90 degrees
- lesser curvature to right, greater curv. to left
- left vagus (anterior wall); right vagus (posterior wall)
duodenum development
formed from foregut and midgut
- beginning part –> celiac trunk
- inferior part –> SMA
- rotate to right w/ stomach
difference b/w child who’s epithelium did not undergo apoptosis in esophagus vs one who’s did not in duodenum?**
esophagus –> trapped food
duodenum –> inhibition of digestion
midgut development
midgut herniates into umbilical cord & begins rotation beginning of 6th week
-GI tract grows faster than abdominal cavity
what happens during malroation of midgut?**
can impinge on SMA –> ishemia to midgut
what is the hindgut supplied by?
IMA
what does the cloaca differentiate into in humans
urogenital sinus, anus, and rectum
hemorrhoids
- internal hemorrhoids –> nonpainful, rectal bleeding, dark red blood
- external hemorrhoids –> painful, bright red blood
where is midgut pain associated with?
umbilical region
stenosis
abnormal NARROWING of lumen
- result of incomplete recanalization or hypertrophy of adjacent structure
- hypertrophic pyloric –> projectile vomiting
- duodenum –> vomit includes bile
atresias
abnormal CLOSING of lumen
- always by failure of recanalization/apoptosis
- esophageal –> from polyhydroamnios mothers
- duodenal –> premies, Down syndrome, polyhydroamnios mothers, vomitus bile
- extrahepatic biliary –> jaundice 2-6 weeks after birth
different atresias
- atresia before stomach –> vomit undigested milk
- atresia of duodenum before bile duct opening –> vomit digested milk w/o bile
- atresia of duodenum after bile duct opening –> vomit digested milk w/ bile
annular pancreas
2 parts of ventral pancreatic duct grow and fuse with dorsal pancreatic duct –> atresia or stenosis to duodenum either before or after bile duct opening
congenital omphalocele
failure of umbilical ring closure (mesenchymal defect)
-intestines found herniated in umbilical cord
umbilical hernia
similar to omphalocele, not as severe
- intestines do not protrude into umbilicus
- protrude only when coughing or crying only
gastroschisis
intestines grow outside body –> protrude through hole near umbilical cord
midgut non rotation
small intestine on right side, large intestine on left
- organs not where they are suppose to be
- volvulus twisting of SMA –> midgut ischemia
- ex. appendicitis symptoms but appendix not where its suppose to be
mixed rotation and volvulus
-cecum below pylorus –> duodenal obstruction
reversed rotation
SMA can compress transverse colon –> stenosis
-stenosis of transverse colon and reduced blood flow through SMA
subhepatic cecum and appendix
cecum does not separate from liver
-can cause appendicitis –> appendectomy
internal hernia
intestinal loop passes through mesenteric defect –> obstructed or strangled
-ex. part of duodenum herniated and trapped behind mesentery wall
midgut volvulus
twisting of midgut over duodenum –> obstructed duodenum
-sometimes bile, sometimes not
omphaloenteric duct remnant
ductal remnants that develop into cysts in umbilicus
- large cysts –> obstruction of GI
- may persist as vitelline artery
- associated with sirenomelia
ileal (meckel) diverticulum
outpouching of ileum w/ vitelline duct/yolk sac remnant
- dark feces, upper GI bleed, obstruct, volvulus
- mimic appendicitis
- diverticulitis if food gets stuck
Hirschsprung disease
congenital megacolon
-failure of neural crest cells to migrate –> no autonomic ganglion cells in myenteric plexus –> no peristalsis –> feces stuck in colon
anorectal birth defects
- imperforate anus - higher in females
- failure of urorectal septum to separate urogenital from anorectal regions
