The Midgut Flashcards
what adult structures form from the cranial end of the primary intestinal loop?
duodenum, jejunum, proximal ileum
what adult structures form from the caudal end of the primary intestinal loop?
distal end of the ileum, cecum, appendix, ascending colon and 2/3rds of transverse colon
at what week does rotation of the primary intestinal loop begin?
week 6
the initial rotation of the PIL occurs around what artery?
the superior mesenteric artery
describe what the physiological herniation is.
the PIL rotates 90 degrees anti clockwise and the gut tube then herniates into the extra embryonic cavity in the umbilical cord to allow further growth of the gut tube
why does the physiological herniation occur?
there isn’t enough space in the abdominal cavity for the full development of the gut tube because of fast growing kidneys and liver
therefore it herniates so it can continue to grow and when it retracts back inside the sizes of the kidneys and liver are more proportionate to the size of the abdominal cavity
when does retraction of the herniated loops occur?
week 10
what part of the midgut enters the abdominal cavity first?
jejunum
what part of the midgut is the last to re enter?
caecum
is there further rotation as it retracts?
yes
180 degrees anti clockwise as it re entered the abdominal cavity
name 3 developmental abnormalities which can occur with the development of the midgut.
omphalocele
gastrochisis
remnants of vitelline duct
what is gastrochisis?
herniation of abdominal contents through the body wall into the amniotic cavity
what is omphalocele?
herniation through an enlarged umbilical ring or retraction of umbilical ring
what happens when there are remnants of the vitelline duct?
the vitelline duct it joins the yolk sac to the midgut
if it remains it forms what is called merkels diverticulum
this may form a fistula or vitelline cyst or ligament
