Embryology (Gastrointestinal Development)

Question 1

Gastrointestinal Development of Foregut (6)

Answer 1

• esophagus
• stomach
• proximal duodenum
• pancreas
• liver
• biliary system

Question 2

Gastrointestinal Development of Midgut (6)

Answer 2

• distal duodenum
• most small intestine
• cecum
• vermiform appendix
• ascending colon
• proximal ½ transverse colon

Question 3

Gastrointestinal Development of Hindgut (5)

Answer 3

• distal ½ transverse colon
• descending colon
• sigmoid colon
• rectum
• superior part of anal canal

Question 4

Esophagus Development

Answer 4

The tracheo-esophageal folds invaginate

Question 5

Innervation of Stomach

Answer 5

Dorsal stomach wall (greater curvature) - right vagus

Ventral stomach wall (lesser curvature) - left vagus

Question 6

Greater Omentum Development

Answer 6

It moves anterior to transverse colon then fuses with it

Question 7

Pancreas Development

Answer 7

Dorsal & ventral pancreatic buds grow between dorsal & ventral mesentary then fuse

Question 8

Billary Development

Answer 8

• Cranial portion froms liver
• Caudal portion forms gallbladder & cystic duct

Question 9

Urorectal Septum

Answer 9

dives between two divisions of cloaca to form separate outlets for urogenital & digestive systems

Question 10

Lower Anal Canal Development

Answer 10

• Develops from proctodeum
• NOT a hindgut derivative

Question 11

Pyloric Stenosis

Answer 11

• Thickening of the smooth muscle in the pyloric region of the stomach
• Narrow canal prevents food from emptying properly from the stomach to the duodenum

Question 12

Duodenal Stenosis

Answer 12

• Lumen is narrowed as a result of failed recanalization
• Symptoms: vomiting
• Associated with polyhydramnios due to low intestinal reabsorption of amniotic fluid

Question 13

Duodenal Atresia

Answer 13

• Lumen is occluded as a result of failed recanalization
• Often associated with other severe congenital abnormalities
• Symptoms: vomiting shortly after birth, stomach distension and “double-bubble” sign
• Associatedwith polyhydramnios due to low intestinal reabsorption of amniotic fluid

Question 14

Congenital Omphalocele

Answer 14

• Persistence of midgut herniation in the umbilical cord
• Herniated intestine fails to return to the abdominal cavity
• Herniated gut is enclosed by the epithelium of the umbilical cord

Question 15

Umbilical Hernia

Answer 15

• Midgut hernia reduces normally, but herniates again through an imperfectly closed umbilicus
• Herniated bowel is covered by subcutaneous tissue and skin

Question 16

Gastroschisis

Answer 16

• Defect in the ventral abdominal wall
• Abdominal viscera extrude through a split in the abdominal wall without umbilical cordinvolvement
• Results from incomplete embryonic folding

Question 17

Ileal (Meckel’s) Diverticulum

Answer 17

• Persistence of the proximal yolk stalk
• May become inflamed and present like appendicitis
• Sometimes contains portions of gastric mucosa in its walls, producing ulceration and bleeding

Question 18

Congenital Megacolon

Answer 18

• Neurological dysfunction that affects the colon
• Abnormality in autonomic ganglia causes failure of peristalsis in the aganglionicsegment
• Intestinal contents accumulate proximal to this point, enlarging the colon

Question 19

Annular Pancreas

Answer 19

• Ventral pancreatic bud fuses with the dorsal bud both ventrally and dorsally
• Forms a ring of pancreatic tissue around the duodenum
• Clinical signs include duodenal obstruction shortly after birth.

Question 20

Anorectal Agenesis

Answer 20

• Rectum ends too far superior
• Can end blindly
• Can make a fistual with the bladder (rectovesical fistula), urethra (rectourethral), vagina (rectovaginal), or vestibule (rectovestibular)