Development of GI tract Flashcards
What gives rise to epithelial lining and glands of digestive system?
endoderm
what surrounds the epithelial tube of the gut?
splanchnic mesoderm
What does splanchnic mesoderm form?
the muscle and connective tissue layers, blood vessels and peritoneal components like mesothelium and connective tissue
where does the primitive gut tube come from?
from folding and a portion of the endoderm lined yolk sac
what is the vitelline duct?
communication between the midgut and the yolk sac, it eventually becomes the core of the umbilical cord
What do the oropharyngeal membrane and cloacal membrane do?
they close the ends of the primordial gut
what suspends the abdominal viscera in the body cavity?
Bilayered dorsal mesentery
what connects the stomach and the liver to the ventral body wall?
Ventral mesentery
What is the Foregut?
region of primitive gi tract with a pharyngeal and proper region
what is the midgut?
region of primitive gut that is inferior to bile duct/pancreatic duct to the junction of the right 2/3ds and left 1/3rd of the transverse colon
What is the hindgut?
left third of transverse colon to cloacal membrane
What are derivatives of the foregut?
Lower respiratory tract, esophagus to duodenum (proximal to bile duct) Liver and biliary apparatus, gallbladder and bile duct.
What is the artery of the foregut?
celiac trunk
Derivatives of the midgut?
inferior duodenum to right 2/3rds of transverse colon
what is midgut artery?
Superior mesenteric artery
Hindgut derivatives?
left 1/3 of transverse colon, to rectum upper anal canal
Artery of Hindgut?
Inferior mesenteric artery
by how much does the stomach rotate initially?
90 degrees
What happens when the circular layer of muscularis externa hypertophies?
it obstructs passage of food, stomach becomes distended, this is called Pyloric stenosis
What does the rotation of the stomach do to the duodenum?
Bends it into a C shape and displaces to the LEFT. It also becomes 2ndarily retroperitoneal
What forms Hepatic diverticulum?
Endodermal thickening over ventral duodenum
What does the hepatic diverticulum grow into?
The septum transversum
what parts of the liver and gallbladder does the endoderm form?
Hepatocytes and biliary apparatus
What does support stroma come from in the liver and gallbladder?
from septum transversu and splanchnic mesoderm
What two parts do the hepatid diverticulum divide into?
Large cranial portion that will give rise to primordium of the liver, and a small ventral outgrowth of the bile duct that gives rise to the gallbladder and the cystic duct
Where do dorsal and ventral bud of pancreas come from?
from endoderm of the duodenum
what happens with rotation of gut tube with the forming pancreas>
it moves the ventral bud dorsally and LEFT the ventral and dorsal buds then fuse
in what direction does rotation move the common bile duct?
left
Which duct of the pancreas usually regresses
the dorsal bud duct
What marks the end of foregut and beginning of midgut in an adult?
the junction between the main pancreatic duct and the accessory duct
What is the umbilical ring?
junction of embryonic ectoderm and the amnion
What passes through the umbilical ring?
connecting stalk/umbilical vessels, yolk stalk, canal connecting intra and extraembryonic cavities, Wharton’s jelly, yolk sac
What is physiological herniation
intestines are outside during week 6 because of midgut elongation and size of liver
Endoderm of hindgut forms lef 1/3 of transverse colon, descending colon,sigmoid, rectum, upper anal canal as well as?
epithelial lining of bladder and urethra
