Embryology

Question 1

Formation of the primitive gut tube is by …

Answer 1

lateral and craniocaudal folding

Question 2

What germ layer does the gut lining form from?

Answer 2

endoderm

Question 3

Initially the mid gut is completely open into the ____1_____ as folding continues it narrows to form a connecting ____2____ it becomes incorporated into the _______3_______

Answer 3

1) yolk sac
2) vitelline duct
3) umbilical cord

Question 4

____1_____ diverticulum appears from the foregut at the end of week 3 and then during weeks 4-7 the ___2____ lengthens rapidly due to descent of the heart and lungs

Answer 4

1) respiratory

2) oesophagus

Question 5

The stomach starts as a __1___ dilation
The __2___ undergoes rapid growth to form the greater curvature The __3___ wall growth is slower resulting in the lesser curvature
There is 90 degree clockwise rotation around the ___4___ axis (LARP)
All this rotation results in the pylorus coming ___5___ and fundus ___6_____

Answer 5

1) fusiform
2) dorsal
3) ventral
4) longitudinal
5) up
6) downwards

Question 6

What are mesenteries and what do they do?

Answer 6

A continuous layer of serous membrane

They attach the gut tube to the anterior (ventral) and posterior (dorsal) walls of the abdomen

Question 7

The omental bursa is also known as the ____1____ and is the _________2____________
This forms from rapid growth of ____3_____ mesentery and stomach rotation around the longitudinal axis

Dorsal mesentery continues to develop as a double layered sac over the small intestine and transverse colon. These layers fuse to extend from the greater curvature of the stomach forming the ______4________

Answer 7

1) lesser peritoneal sac
2) peritoneal space posterior to the stomach
3) dorsal
4) greater omentum

Question 8

The duodenum as both a ______

Answer 8

foregut and midgut structure

Question 9

As the stomach rotates what happens to the duodenum?

Answer 9

Duodenum moves away from the midline to there right side of the abdominal cavity. Dorsal mesentery will fuse with peritoneum covering the posterior abdominal wall resulting in duodenum parts 2/3 becoming retroperitoneal

Question 10

What causes physiological herniation of the midgut?

Answer 10

Rapid growth and expansion of the liver

Question 11

What germ layer do liver cells and the lining of the biliary tree form from?

Answer 11

Endoderm

Question 12

What germ layer does the spleen form from?

Answer 12

The mesoderm- it is not formed from the gut tube