Small Bowel Embryology Flashcards
(15 cards)
When does the primitive gut tube form?
At 4 weeks
What gives rise to the epithelial lining of the GIT?
Endoderm
What gives rise to the muscle and other non-epithelial layers of the GIT?
The splanchnic mesoderm
When does embryological herniation occur? Why?
Herniation occurs at 5 weeks, because growth outstrips space in the peritoneal cavidy
The midgut has a cranial and a caudal limb. What is found at the apex between these two limbs?
The vitelline duct
What is a persistent remnant of the vitelline duct called in adults?
A meckel’s diverticulum
What does the vitelline duct join the gut tube to?
The yolk sac
At what week of development does the bowel complete returning to the abdomen? What does it complete first?
The bowel completes returning to the abdomen at 10 weeks, after completing a 270 degree roast at ion
Which limb of the mid gut grows to cause rotation? How does it return to the abdomen?
The cranial limb grows, with rotation and reduction into the abdomen, with the jejunum lying on the left side.
The caecum forms as a diverticulum on what limb of the mid gut? At what point during reduction does it enter?
On the caudal limb of the mid gut. It enters last
Where does the caecum sit when it first enters the abdomen? What does it do after this?
The caecum sits in the RUQ on re-entry. It then descends to the RIF.
What week do villi develop?
The 9th week
What week do crypts develop?
The 10th week
List four types of small bowel cells
Enterocytes
Goblet cells
Paneth cells
Enteroendocrine cells
What makes up 95% of small bowel cells? What is their function?
Enterocytes - intestinal absorptive cells
