Lecture 6-Embryology II Flashcards
What is the primary intestinal loop?
Midgut elongates and runs out of space so makes a loop that has superior mesenteric artery (SMA) as its axis and is connected to the yolk sac by vitelline duct and has cranial and caudal limbs
What is physiological herniation?
Normal process during 6th week where growth of primary intestinal loop is very rapid, as is the growth of the liver. The abdominal cavity is too small for both two the intestines herniate into the umbilical cord
True or false: midgut rotation is 2 90º turns
FALSE - 3 90º turns
True or false: during midgut rotation, the duodenum is pushed behind the transverse colon
TRUE
How does a left-sided colon develop?
Incomplete rotation - midgut loop only makes one 90º rotation
What causes the transverse colon to pass posterior to the duodenum?
Reversed rotation - midgut loop makes one 90º turn clockwise instead of anticlockwise
What is volvulus and what can it lead to?
Twisting - structures that aren’t mobile become mobile
Can lead to strangulation and ischaemia -> bilious vomiting
True or false: the vitelline duct is a remnant of the yolk stalk
TRUE
What is a vitelline cyst?
Duct forms fibrous strands
What is a vitelline fistula?
Direct communication between umbilicus and intestinal tract
What is Meckel’s diverticulum?
Ileal diverticulum, can contain ectopic gastric or pancreatic tissue
What is recanalisation?
In some structures (oesophagus, bile duct), cell growth becomes so rapid that lumen becomes partially/completely obliterated and recanalisation restores lumen
What is pyloric stenosis?
Hypertrophy of circular muscle in region of pyloric sphincter
Common in infants and can lead to projectile vomiting
What is gastroschisis?
Failure of closure of abdo wall during folding of the embryo, leaving gut tube and derivatives outside body -> necrosis of small parts of contents
What is omphalocoele/exomphalos?
Persistence of physiological herniation
