2.2 Development of the Peritoneum and the Foregut

Question 1

What are the three divisions of the gut?

Answer 1

Foregut, midgut, hindgut

Question 2

List the organs that are developed from the foregut

Answer 2

Oesophagus, stomach, pancreas, liver, gallbladder, 1/3rd proximal duodenum

Question 3

List the organs that are developed from the midgut

Answer 3

Distal 2/3rd of duodenum, jejunum, ileum, cecum, ascending colon, 2/3rds of transverse colon

Question 4

List the organs that are developed from the hindgut

Answer 4

Distal 2/3rd of transverse colon, descending colon, sigmoid colon, rectum, upper anal canal
+ internal lining of bladder and urethra

Question 5

Name the aortic branches that supply the:

i. ) Foregut
ii. ) Midgut
iii. ) Hindgut

Answer 5

i. ) Celiac trunk
ii. ) Superior mesenteric artery
iii. ) Inferior mesenteric artery

Question 6

From which embryological area do the body cavities derive from?

Answer 6

The intraembryonic coelom

Question 7

What structure lines the abdominal cavity?

Answer 7

The peritoneal membrane

Question 8

What is a mesentery?

Answer 8

A double layer of peritoneum suspending the gut tube from the abdominal wall. This allows blood vessels and nerves to supply the gut tube.

Question 9

What type of mesoderm forms the mesenteries?

Answer 9

Splanchnic mesoderm

Question 10

Where is the dorsal mesentery located?

Answer 10

Suspends the entire gut tube from the dorsal body wall

Question 11

Where is the ventral mesentery located?

Answer 11

Only in the foregut region

Question 12

How is the cavity containing the foregut divided?

Answer 12

Ventral and dorsal mesenteries form a left and right sac around the foregut

Question 13

What becomes of the left sac surrounding the foregut?

Answer 13

The left sac contributes to the greater sac

Question 14

What becomes of the right sac surrounding the foregut?

Answer 14

The right sac becomes the lesser sac and moves to sit behind the stomach

Question 15

What is an omenta?

Answer 15

Specialised regions of the peritoneum.

Question 16

What is the Greater Omentum formed from?

Answer 16

The dorsal mesentery

Question 17

What is the Lesser Omentum formed from?

Answer 17

The ventral mesentery

Question 18

What is conducted in the free edge where the ventral mesentery ends after the foregut?

Answer 18

The portal triad

Question 19

List 4 things that are achieved by the rotation of the stomach

Answer 19

Greater and Lesser curvatures lie on the left and right
Cardia and pylorus move horizontally
Vagus nerves are moved anterior and posterior instead of left and right
Moves lesser sac behind the stomach
Creates the greater omentum

Question 20

What is a peritoneal reflection?

Answer 20

A joint between mesentery and peritoneum where the border changes direction

Question 21

What does the term ‘retroperitoneal’ mean?

Answer 21

A structure that is not suspended within the abdominal cavity. They do not have a mesentery

Question 22

What does ‘secondary retroperitoneal’ mean?

Answer 22

Began development invested by peritoneum and had a mesentery but with growth the mesentery is lost.

Question 23

Give an example of a secondary retroperitoneal organ

Answer 23

Pancreas
Distal 2/3rds of duodenum
Ascending colon
Descending colon

Question 24

List all of the retroperitoneal organs

Answer 24

Suprarenal glands
Aorta
Duodenum

Pancreas
Ureters
Colons (ascending and descending)
Kidneys
Esophagus
Rectum

Question 25

Where does the foregut extend to?

Answer 25

The lung bud to the liver bud

Question 26

What forms to separate the oesophagus from the trachea?

Answer 26

Respiratory diverticulum

Question 27

Where does the liver develop from?

Answer 27

The hepatic bud within the ventral mesentery

Question 28

What surrounds the liver?

Answer 28

Posteriorly: lesser omentum
Anteriorly: falciform ligament

Question 29

Where does the duodenum develop from?

Answer 29

Caudal foregut and cranial midgut

Question 30

How does the duodenum become retroperitoneal?

Answer 30

The stomach rotation pushes it against the posterior abdominal wall and the membranes fuse by fusion fascia

Question 31

At what week does the embryo fold?

Answer 31

Week 4