Development of the Digestive System II Flashcards
What are the mesenteries in origin?
Mesoderm
What are the mesenteries derived from?
Splanchnic mesenchyme that surrounds the primitive gut
What is the morphogenesis of the mesentery influenced by?
Morphogenesis of the gut
In the oesophagus what does the mesenchyme develop into?
Muscle
What type of muscle is the branchial arch mesenchyme?
Skeletal
What type of muscle is the splanchnic muscle?
Smooth
What is the primitive stomach suspended from?
Dorsal wall by dorsal mesentery
What is dorsal mesentary called?
Mesogastrium
What does the stomach grow into?
dorsal and ventral mesogastria
What does extra growth of dorsal surface lead to?
Loop of dorsal mesogastria to the greater omentum
What direction of the rotation does the stomach turn?
Clockwise rotation
Where is the small pouch of stomach formed between?
Dorsal peritoneum and greater omentum
What is the small pouch also known as?
Lesser sac or omental bursa
What is the entrance to the stomach called?
Epiploic foramen or foramen of wilmslow
How is the ascending and descending colon formed retroperitoneal?
mesentery of a. and d. colon fuses with parietal peritoneum and dissappears
What does the colon press the duodenum against?
Posterior abdominal wall
What happens to duodenum once on posterior of abdomen?
duodenum mesentary is absorped so duodenum and most of pancreas is retroperitoneal
What does the mesentary of trasnverse colon fuses with?
Dorsal mesgastrium
which colon retain its mesentary?
Sigmoid
Where does the pancreas develop from?
2 outgrowths of endodermal epithelium of caudal part of foregut
What are the 2 outgrowths of endodermal epithelium that pancreas grows from?
Dorsal and Ventral pancreatic buds
What does the pancreas rotate around to fuse to?
Migration of latter and bile duct around duodenum to fuse with former
What happens when the ducts join?
Main pancreatic duct and empty with bile duct into duodenum
Where do the Liver and biliary apparatus develop from?
Outgrowths of endodermal epithelium of caudal part of foregut
What is the caudal part of the foregut?
Hepatic diverticulum
What does the hepatic diverticulum consists of?
Rapidly proliferating cells that extend into septum transversum
What is the septum transversum?
Mass of mesodermal cells between pericardial cavity and yolk stalk
What does the septum transversum form?
Most of diaphragm and ventral mesentary
What does the hepatic diverticulum form?
Cranial and caudal parts of liver
What happens to former liver?
grows large and becomes parenchyma of liver
What does the latter liver do?
Is small and creates gall bladder and cystic duct
What does the cystic duct develop as?
Solid tube
What happens if the cystic duct fails to canalise?
Extrahepatic biliary atresia
Where does the spleen develop from?
Mesenchymal cells between layers of dorsal mesentary of stomach
What is the appearance of spleen in foetal life?
lobulated but lobes fuse before birth become notches in superior border of adult spleen
