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Flashcards in 2. GI embryology Deck (20):
1

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

2

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

3

primitive gut tube epithelial behaviour

early in development --> epithelial lining of the gut tube proliferates rapidly and obliterates the lumen --> later, recanalization occur

4

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

5

Ventral wall defects - types and result

Developmental defects due to failure of:
ƒƒ Rostral fold closure—sternal defects
ƒƒ Lateral fold closure—omphalocele,
gastroschisis
ƒƒ Caudal fold closure—bladder exstrophy

6

Gastroschisis

extrusion of abdominal contents
through abdominal folds (typically right of
umbilicus); not covered by peritoneum

7

Omphalocele

persistence of herniation of
abdominal contents into umbilical cord,
sealed by peritoneum

8

• A patient has a malformed gastrointestinal tract from pharynx to duodenum. What part of the embryo had impaired development?

Foregut

9

• 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)

10

• A developing embryo suffers a malfunction of the midgut. Which region of the gastrointestinal tract will be impacted?

Duodenum to the transverse colon

11

• 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)

12

• 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

13

• 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)

14

• A baby with bladder exstrophy presents to the clinic. What type of folds failed to close properly during embryologic development?

Caudal folds

15

• A baby presents with sternal defects. Failure of what type of folds to close properly caused this clinical scenario?

Rostral folds

16

• 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)

17

• In the sixth week, the midgut herniates through this structure, then returns to the abdominal cavity (week 10) and rotates around the SMA.

Umbilical ring

18

• A newborn presents with severe abdominal distention. Around which artery is the baby's midgut malrotated?

Superior mesenteric artery

19

• 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

20

• An infant fails to pass meconium at birth. X-ray shows apple-peel atresia of the lower GI tract. What most likely happened in utero?

Vascular accident causing jejunal, ileal, and colonic atresia (characteristic apple-peel atresia on x-ray)

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