Development of GI System (Exam 2) Flashcards
What is the function of the vitelline duct
maintains continuity between the yolk sac and primitive gut tube
What layers contribute to the gut tube
all 3 germ layers
What does the endoderm contribute to the gut tube
endothelial lining from pharynx to upper anal canal
epithelium of all evagination: accessory GI organs
What does the mesoderm contribute to the gut tube
CT and smooth muscle
What does the ectoderm contribute to the gut tube
epithelium at rostral and caudal ends of tube
neural crest (neuroectoderm) contributes to ganglia
What parts of the yolk sac remain outside the embryo
allantois and remaining yolk sac
What provides communication between gut and yolk sac
vitelline duct
What is the stomodeum
primitive oral cavity
What is the proctodeum
dimple over the cloak that indicates where the anus will form
What are the 3 portions of the gut tube
foregut
midgut
hindgut
Where is the foregut
buccopharyngeal membrane to 2nd part of duodenum
Where is the midgut
3rd part of duodenum to 2/3 transverse colon
Where is the hindgut
lower 1/3 of transverse colon to cloacal membrane
What artery supplies the foregut
celiac artery
What artery supplies the midgut
superior mesenteric
What artery supplies the hindgut
inferior mesenteric
How will the respiratory system develop
respiratory diverticulum appears in the ventral wall of the esophagus
What partitions the esophagus and respiratory primordium
tracheosophageal septum
What are the common esophageal anomalies
proximal blind end with distal fistula
What will a fistula in the esophagus result in
respiratory infections and choking
What will a blind end pouch result in
vomiting and failure to thrive
What produces stomach curvatures
differential growth
What are the rotations of the stomach
90 degrees in axial plain
45 degrees in caudal plane
What occurs to the vagal trunks with rotation
once left and right
now anterior and posterior
How is the stomach innervated
vagus
What is the greater omentum derived from
folds of dorsal mesentery
Where is the greater omentum found
hanging off greater curvature and posterior wall
What rotation form greater omentum
longitudinal rotation
What is the lesser omentum derived from
ventral mesentery
What does the duodenum arise form
caudal end of foregut and rostral end of midgut
What occurs to the duodenum as the stomach rotates
pulls duodenum superiorly and to the right, results in C-shaped duodenum
What occurs to the duodenum in the 2nd month
obliterated, but then recanalyzed by apoptosis
If the duodenum is not recanalyzed what occurs
duodenal atresia
What is characteristic on X-ray of duodenal atresia
double bubble
What are signs and symptoms of duodenal atresia
bilious vomiting
What organs will originate as outgrowths of duodenum
pancreas
liver
gallbladder
What part of the duodenum gives rise to pancreas, liver, gallbladder
part 2
How does the liver form
bud grows out into ventral mesentery and penetrates septum transversum
What does endoderm contribute to in the liver
parenchyma and lining the biliary ducts
What does mesoderm contribute to in the liver
hematopoietic, Kupffer cells, and CT
How does the gallbladder form
cystic duct develop as ventral outgrowths from bile ducts
What occurs to the ducts of the pancreas during develop
solidify and recanalize
How does the pancreas from
in two parts-ventral and dorsal
differential growth leads to fusion of buds (ventral swings to dorsal)
Most of the pancreas substance comes from what bud
dorsal bud
Most of the pancreatic ducts come from what bud
ventral
What does the ventral bud of the pancreas contribute to
uncinate process
Where does the secreting cells of pancreas come from
endoderm
Where do the CT of pancreas come from
mesoderm
Where does the main pancreatic duct form from
distal part of dorsal pancreatic duct and entire ventral pancreatic duct
Where does the accessory duct of pancreas come from
proximal part of dorsal bud
Where does the accessory duct of pancreas open into
superior to main duct
What is annular pancreas
malrotation of the ventral pancreatic bud: rotates anteriorly or not at al
What does annular pancreas result in
duodenum encircled and causes stenosi
What are symptoms of annular pancreas
non bilious vomiting
What defect results in bilious vomiting
duodenal atresia
What defect results in non-bilious vomiting
annular pancreas
How is the primary intestinal loop formed
rapid growth of gut tube and mesentery
How will the midgut obtain anatomical position
due to differential growth, midgut herniates through umbilical ring
What occurs as the midgut herniates
90 degrees of counterclockwise rotation
How long does the midgut remain outside the body
1 month
What occurs as the midgut returns to the body
180 degrees of counterclockwise rotation
What part of the midgut returns first after physiological herniation
jejunum
What part of midgut returns last after physiological herniation
cecal bud
What is formed after the midgut returns to the abdomen
appendix is formed
What causes Meckel’s diverticulum
persistence of vitelline duct leads to outpouching
What are the rule of 2’s for Meckel’s diverticulum
2% of population presenting age 2 y/o 2'' long occurs 2' from ileocecal valve 2x more common in males find 2 types of ectopic tissue (gastric pancreatic)
What are the different types of vitelline duct abnormalities
Meckel’s diverticulum
Vitelline cyst
Vitelline fistula
What is umbilical hernia
protrusion of abdominal contents into the umbilicus; usually due to weakness in the wall
What is the cloaca
common opening for excretory, digestive, and reproductive products
What lines the cloaca
endoderm
What is urorectal septum
formed from two folds that serve to divide the cloaca
What does the urorectal septum divide the cloaca into
recto-anal canal
urogenital sinus
What is the cloacal membrane divided into
urogenital membrane
anal membrane
How is the lower anal canal formed
invagination of surface ectoderm
What is the pectinate lien
dividing line between ectoderm and endoderm
What is the anal pit
invagination of ectoderm from proctodeum
What is an imperforate anus
anal membrane fails to break down and nothing can leave anal canal
What will result from a persistent cloaca
one pouch that collects urine and feces
What is Hirschsprung’s disease
improper migration of NCC into the developing hindgut. NCC give rise to ganglia.
Wat causes achalasia
damage to ganglion cells of the myenteric plexus
What results in achalasia
dilated esophagus with tonically contracted LES= dysphagia
What is congenital hypertrophic pyloric stenosis
thickening of pylorus of stomach, obstruction and distention of stomach
projectile vomiting
What will result from extra hepatic biliary atresia
jaundice occurs shortly after birth, stool is “clay colored” and urine is dark
What is the most common anomaly of the pancreas
pancreas divisum
what occurs in pancreas divisum
abnormal development of the pancreatic duct system, accessory duct drains nearly the entire pancreas via the minor papilla
What does pancreas divisoum increase one’s risk of
pancreatitis
What is a choledochal cyst
congenital dilation of the common bile duct
What is choledochal cyst associated with
increased stone formation
What are symptoms of esophageal atresia
vomiting of uncurdled milk
What are symptoms of gastric atresia
vomiting of curdled milk
What are symptoms of duodenal atresia
vomit containing bile
