Flashcards in GI embryology Deck (43)
foregut, midgut and hindgut divisions
foregut - pharynx to duodenum
midgut - duodenum to proximal 2/3 colon
hindgut - distal 1/3 colon to anal canal
90 degrees clockwise
failure of lateral fold closure causes
gastroschisis or amphalocele
duodenal atresia due to...
failure to recanalize (trisomy 21)
jejunal, ileal, or colon atresia due to
6th week it herniates through the umbilical ring
10th week returns to abd cavity and rotates around the SMA
=270 degree couterclockwise turn (view from below)
90 during herniation and 180 as it goes back
extrusion of abd contents through abd folds NOT covered by peritoneum
persistence of herniation into umbilical cord; IS sealed by peritoneum (not incontact with amniotic fluid)
EA with distal TEF
drooling, choking and vomiting with first feeding
TEF allows air to enter stomach visible on CXR
cannot pass a nasogastric tube into stomach!
presents with polyhydramnios
isolated EA CXR
CXR shows gassless abdomen
congential pyloric stenosis
hypertrophy of pylorus causes obstruction
palpable olive mass in epigastric region and nonbilious projectile vomiting at 2-6 weeks old
failure of LES to relax
oligohydramnios vs poly hydramnios
oligo - too little amniotic fluid, decreased volume
poly - too much; fetus isnt swallowing
in pharyngeal gut, lining is derived from?
cartilage, muscles, and nerves from?
in for, mid, and hind guts,
epithelial lining is from?
muscles and CT from?
enteric nervous system from?
gut tube is suspended by
midgut is temporarily connected to yolk sac by____
what factor regulates epithelial-mesenchyme interactions?
SHH (sonic hedgehog)
SHH induces the creation of
HOX which diactates the head to tail regions
branches of aorta to supply
fg = celiac
mg = Superior mesenteric
hg = inferior mesenteric
oropharyngeal membrane to the respiratory diverticulum
left anterior, right posterior
development of stomach curvatures
dorsal side grows faster --> lesser and greater curvatures
supra adrenal glands
duodenum (2nd and 3rd)
pancreas (except tail)
colon (ascending and descencing)
During the third week of development, the allantois protrudes into the area of the urogenital sinus. Between the 5th and 7th week of development, the allantois will become the urachus, a duct between the bladder and the yolk sac. A patent allantois can result in urachal cyst.
improper fixation of mesentery -->
fecal discharge at umbilicus is due to
meckels diverticulum does not connect with outside; blunt outpouch that is connected to umbilicus internally
absence of enteric ganglia in bowel wall due to defect in neural crest migration
causes megacolon, constipation and obstruction
anal canal differences above and below pectinate line
above: hindgut endoderm, autonomic visceral nerves, inf mesenteric artery, portal vein, internal iliac lymph nodes
below: proctodeum ectoderm, pudendal nerve/somatics (sensitive to stimuli), internal pudendal artery, caval venous system, superficial inguinal lymph nodes