GI Embryology

Question 1

what germ layer forms the gut tube?

Answer 1

endoderm

Question 2

what is the vitelline duct?

Answer 2

the tube that joins the yolk sac to the midgut lumen of developing foetus (it becomes incorporated into the umbilical cord)

Question 3

what is the allantois?

Answer 3

an extension of the developing hindgut

Question 4

what midline branch of the aorta supplies the foregut?

Answer 4

coeliac trunk

Question 5

what midline branch of the aorta supplies the midgut?

Answer 5

superior mesenteric artery

Question 6

what midline branch of the aorta supplies the hindgut?

Answer 6

inferior mesenteric artery

Question 7

what is the tracheoesophageal septum?

Answer 7

the septum which forms to separate the trachea and foregut allowing formation of the oesophagus

Question 8

what does the dorsal wall of the stomach’s inital fusiform dilation become and why?

Answer 8

the greater curvature as it grows rapidly

Question 9

what does the ventral wall of the stomach’s inital fusiform dilation become and why?

Answer 9

the lesser curvature as it grows more slowly

Question 10

what kind of rotation of the stomach brings the pylorus upwards and the fundus dowards?

Answer 10

anteroposterior

Question 11

what fixes the intestines the posterior abdominal wall?

Answer 11

the mesentery

Question 12

the dorsal mesentery develops as a double layered sac over the small intestine and the transverse colon and then fuses to form the ______

Answer 12

greater omentum

Question 13

the ____ mesentery is involved in the formation of the omental bursa (lesser sac) and the greater omentum

Answer 13

dorsal

Question 14

in development the ____ mesentery fuses with the ______?

Answer 14

dorsal

peritoneum

Question 15

what are the two parts of primary intestinal loop that make the midgut?

Answer 15

crainial (cephalic) limb

caudal limb

Question 16

what does the cranial (cephalic) limb of the primary intestinal loop become?

Answer 16

distal duodenum
jejunum
upper ileum

Question 17

what does the caudal limb of the primary intestinal loop become?

Answer 17

lower ileum
cecum
ascending colon
proximal 2/3rd transverse colon

Question 18

what is the cloaca?

Answer 18

the terminal end of the hindgut

Question 19

what it the cloaca partitioned into by the urorectal septum?

Answer 19

the upper rectum/anal canal

urogenital sinus

Question 20

what is the hepatic diverticulum?

Answer 20

liver bud

Question 21

what does the cranial part of the liver bud become?

Answer 21

liver

Question 22

what does the caudal part of the liver bud become?

Answer 22

bile duct

Question 23

what forms the hepatic sinusoids? (2)

Answer 23

intermingling of hepatic cords (groups of hepatocyte) and vitelline veins

Question 24

what are vitelline veins?

Answer 24

veins that drain poorly oxygenated but nutrient rich blood from the yolk sac

Question 25

what germ layer produced the liver cells and the biliary tree lining?

Answer 25

endoderm

Question 26

what does the septum transversum produce? (3)

Answer 26

hematopoietic cells
Kupffer cells
connective tissue

Question 27

what does the pancreas form from?

Answer 27

the dorsal pancreatic bud

Question 28

what germ layer is the spleen derived from?

Answer 28

mesoderm

Question 29

what is meckel’s diverticulum?

Answer 29

the persistence of the vitelline duct which forms an outpouching of the ileum (remember the rules of 2)

Question 30

what congenital abnormality can cause a congenital hiatal hernia or a hiatal hernia later in life?

Answer 30

short oesophagus

Question 31

what is omphalocele?

Answer 31

the failure of the intestinal loop to return to the abdomen. presents at the base of the umbilical cord

Question 32

what is gastrochisis?

Answer 32

the protrusion of abdominal content through the wall lateral to the abdominal wall

Question 33

what can happen when the pancreas encircles the duodenum?

Answer 33

constriction or total occlusion of the duodenum