7: Embryology

Question 1

What is the communication from the midgut to the yolk sac during development?

Answer 1

Vitelline duct

Question 2

Which germ layer does the epithelium, ducts and glands come from?

Answer 2

Endoderm

All GI stuff comes from the endoderm

Question 3

Which germ layer does the lamina propria, smooth muscle and connective tissue come from?

Answer 3

VISCERAL mesoderm

Question 4

During development, mesenteries form on the ventral and dorsal aspects of the gut. As organs become retroperitoneal, most of these mesenteries are lost.

What is an example of a ventral mesentery?

Answer 4

Falciform ligament

Lesser omentum

Question 5

During development, mesenteries form on the ventral and dorsal aspects of the gut. As organs become retroperitoneal, most of these mesenteries are lost.

What is an example of a dorsal mesentery?

Answer 5

Dorsal mesogastrium

Dorsal mesoduodenum

Dorsal mesocolon

Question 6

In Week 4, the (cranial / caudal) end of the oesophagus dilates to form which shapes of the stomach?

Answer 6

caudal

Greater and lesser curvatures

Question 7

After its caudal dilation, in which direction does the gut tube project to form the stomach?

Answer 7

Dorsally (posteriorly)

Question 8

By how many degrees does the gut tube rotate to form the stomach?

Answer 8

90º

Question 9

Which structures, associated with the stomach, form after the rotation is complete?

Answer 9

Greater and lesser sacs

Greater and lesser omenta

Falciform ligament

Question 10

Where in the duodenum does the foregut stop and the midgut begin?

Answer 10

Between the 2nd and 3rd parts

Question 11

What is the septum transversum?

Answer 11

Developmental structure which gives rise to the diaphragm and ventral mesentery (lesser omentum, falciform ligament)

Derived from the mesoderm

Question 12

The liver buds off the gut tube during development. Into which structure does it bud?

Answer 12

Septum transversum

Question 13

Which organ buds off the endoderm of the gut tube into the mesoderm of the septum transversum?

Answer 13

Liver

Question 14

Which germ layer forms the lining of the biliary tree?

Answer 14

Endoderm

Question 15

During development, the pancreas has ___ buds.

Answer 15

two

Question 16

At the beginning of its development, the pancreas buds off the gut tube in two places. What are these two buds called?

Answer 16

Ventral pancreatic bud

Dorsal pancreatic bud

Question 17

The ventral pancreatic bud rotates ___ around the dorsal aspect of the gut tube and then ___ with the dorsal pancreatic bud.

Answer 17

180º

fuses

Question 18

What is the embryological structure which eventually becomes the gall bladder?

Answer 18

Cystic diverticulum

Question 19

During development, the pancreas moves from ___ to ___.

(retroperitoneal / intraperitoneal)

Answer 19

intraperitoneal to retroperitoneal

Question 20

Does the spleen bud from the gut tube?

Answer 20

No

Question 21

Which germ layer does the spleen come from?

Answer 21

Mesoderm

because it’s related to the VASCULAR system

Question 22

During the majority of its development, the intestines are (inside / outside) the embryo.

Answer 22

outside

Question 23

Main congenital GI tract defects to know:

Vitelline duct problems - Meckel’s diverticulum, cysts, ligaments and fistulae

Fistulae or blind ends elsewhere - urorectal, anal pits etc.