Gut Development 2 Flashcards
The primitive gut tube is formed from the … sac in folding of the embryo. The …. membrane is cranial and caudally the diverticula ends with the … membrane
Yolk
Buccopharyngeal
Cloacal
What happens when the midgut elongates quickly and no longer fits in the abdominal cavity?
Makes a loop with a cranial and a caudal limb. This physiologically herniates into the umbilicus with the superior mesenteric artery as its axis.
What connects the midgut loop and the yolk sac?
The vitelline duct.
In which week is the growth of the primary loop very rapid?
6
In week 6 which other organ grows quickly meaning there isn’t enough room for it and the fast growing mid gut?
The liver
How many degrees must the herniation turn to get the correct orientation of midgut viscera?
270 degree rotation with both cranial and caudal ends fixed.
After rotation of the midgut herniation what must depend?
Cacecal bud
What embryological problem would give rise to a left sided colon?
Incomplete rotation (midgut only rotates 90 degrees)
Reversed midgut rotation results in what visceral arrangement?
Transverse colon posterior to duodenum
What is the risk of a midgut abnormality and when would these problems most likely present?
Increased bowel mobility can lead to volvulus that can strangulate and become ischaemic. If a midgut defect is a problem its commonly seen in the neonatal period. (note a lot are asymptomatic)
If the caecal bud doesn’t descent what defect is seen?
Subhepatic caecum
List three issues that involve persistence of the vitelline duct.
Vitelline cyst
Vitelline fistula
Meckels diverticulum
What is the problem with Meckel’s diverticulum?
Risk of volvulus from the out pouching of midgut
Can contain epigastric or pancreatic tissue - secretions cause inflammation as the midgut is not equipped for these foregut tissues secretions
What would leak out of the belly button after a Vitelline fistula (yolk sac remnants)?
Intestinal contents
Why does meckel’s diverticulum follow the rule of 2s.
2% of population
2 feet from ileocaecal valve
detected usually in under 2s
2:1 male to female
Where is the cell growth of gut structures so fast that it closes the lumen and later requires recannulisation?
Oesophagus, buke duct and the small intestine
Incomplete recannulisation leads to what defects?
Atresia (obliterated lumen) or stenosis (narrow lumen)
What other than failure to reconciles may give rise to atresia or stenosis?
vascular incidents
What is pyloric stenosis?
Hypertrophy of the smooth muscle at the pyloric sphincter - not a recannulisation error. Common in infants and leads to projectile vomiting.
What is gastroschisis?
Failure of anterior abdominal wall closure during embryonic folding. Uncovered gut tube derivatives outside the body cavity seen antenatally.
How would you deliver a baby with gastroschisis?
C section
Normally isolated condition so only risk is a small amount of bowel necrosis- monitor and treat.
A persistence of physiological midgut herniation leading to gut material being seen in a translucent membrane protruding from the umbilicus is called what?
Omphalocoele/ exopmphalos
How would you distinguish between exomphalos and a umbilical hernia?
Umbilical hernia is covered by skin and subcutaneous tissue. Important to distinguish as umbilical hernias tend to self resolve, but ompahlocoele is not generally an isolated defect.
The urinary bladder epithelium is derived from which embryological gut segment?
hindgut
