Flashcards in Digestive Development 2 Deck (26):
What artery supplies the midgut?
How does the midgut communicate with the yolk sac in early development
When the midgut and its mesentery rapidly expands, particularly cephalopod end, what does structure does this cause to develop?
Primary intestinal loop
Because the intestines grow too big for the body cavity, what happens?
They temporarily herniate outside the body cavity into the umbilical cord and then return
How does the primary intestinal loop rotate?
Around the axis of the superior mesenteric artery about 270*
When do the intestines return to the body?
What appears on the cecal bud as the intestines are coming back into the body?
The appendix develops while the cecum is descending so what is its most common position?
What is the cloaca?
Endoderm lined cavity that is covered at the ventral boundary by ectoderm (forms cloacal membrane)
What happens when the cloacal membrane ruptures?
7th week - opening to the hind gut forms
What's the blood supply and derivatives and mucosa of the upper end of the anal canal?
Superior rectal arteries (branch of superior mesenteric)
Simple columnar epithelium
What's the blood supply and derivatives and mucosa of the lower end of the anal canal?
Inferior rectal arteries (branch of internal pudendal)
Stratified squamous epithelium
What is the dividing line between upper anal canal and lower anal canal?
Herniation of the bowels lateral to the umbilicus not contained in the umbilical cord
What can increase the chances of gastroschisis occuring?
But NOT chromosomal abnormalities
What can be detected in amniotic fluid that is elevated with gastroschisis
What is omphalocele
Herniation of the abdominal viscera through an enlarged umbilical ring covered by the amnion
Omphalocele is highly associated with what?
What is meckels diverticulum?
A remnant of the Vitelline duct found on the ileum by the umbilicus
Is meckels diverticulum clinically significant?
Only if it contains heterotopic pancreatic tissue or gastric mucosa
What is a gut atresia
Congenital absence of an opening or lumen
What is a gut stenosis
Narrowing of the gut orifices or openings
Where do most gut stenosis and atresias occur?
In the duodenum because it's closed off and recanalized
What cause rectourethral and rectovaginal fistulas
Abnormalities in formation of the cloaca and/or the urorectal septum
What causes rectoanal atresias