Flashcards in 2. GI embryology Deck (20)
normal gastrointestinal embryology - structures that give rise to
1. Foregut --> pharynx to duodenum ( including liver , gallbladder and pancrease)
2. Midgut ---> duodenum to proximal 2/3 of transverse colon
3. Hindgut --> distal 1/3 transverse colon to anal canal above pectinate line
the primitive gut tube is formed from
the incorporation of the dorsal part of the yolk sac into embryo due to craniocaudal folding and lateral folding of the embryo --> it extends drom oropharyngeal membrane and is divided into : 1. Foregut 2. Midgut 3. Hindgut
primitive gut tube epithelial behaviour
early in development --> epithelial lining of the gut tube proliferates rapidly and obliterates the lumen --> later, recanalization occur
Midgut development: (and times
6th week—physiologic midgut herniates through umbilical ring
10th week—returns to abdominal cavity + rotates around superior mesenteric artery (SMA),
total 270° counterclockwise
Ventral wall defects - types and result
Developmental defects due to failure of:
Rostral fold closure—sternal defects
Lateral fold closure—omphalocele,
Caudal fold closure—bladder exstrophy
extrusion of abdominal contents
through abdominal folds (typically right of
umbilicus); not covered by peritoneum
persistence of herniation of
abdominal contents into umbilical cord,
sealed by peritoneum
• A patient has a malformed gastrointestinal tract from pharynx to duodenum. What part of the embryo had impaired development?
• In a patient with a hiatal hernia, the herniated structure was originally derived from the ____ (foregut/midgut/hindgut).
Foregut (herniation of the proximal stomach through the diaphragm)
• A developing embryo suffers a malfunction of the midgut. Which region of the gastrointestinal tract will be impacted?
Duodenum to the transverse colon
• The part of the colon supplied by both the hepatic and splenic flexures is derived from the ____ (foregut/midgut/hindgut).
Midgut (the transverse colon is supplied by both the hepatic and splenic flexures)
• A developing embryo suffers damage to the hindgut. As an adult, what structures of the GI tract will be affected?
The distal transverse colon to the rectum
• An extrusion of abdominal contents not covered by the peritoneum is found on a newborn undergoing surgery. Name this diagnosis.
Gastroschisis (failure of the lateral body folds to fuse)
• A baby with bladder exstrophy presents to the clinic. What type of folds failed to close properly during embryologic development?
• A baby presents with sternal defects. Failure of what type of folds to close properly caused this clinical scenario?
• An extrusion of abdominal contents into the umbilical cord is covered by the peritoneum on a newborn having surgery. Name this diagnosis.
Omphalocele (sealed by peritoneum)
• In the sixth week, the midgut herniates through this structure, then returns to the abdominal cavity (week 10) and rotates around the SMA.
• A newborn presents with severe abdominal distention. Around which artery is the baby's midgut malrotated?
Superior mesenteric artery
• A baby is born with trisomy 21 and diagnosed with duodenal atresia. How would you explain this GI tract malformation to the parents?
Failure of the duodenum to recanalize