Gut Development 1

Question 1

How do we develop an anterior gut wall?

Answer 1

folding of the embryo gives a gut within a cavity

Question 2

When does the embryo fold?

Answer 2

4th week gestation

Question 3

What embryological tissue is the gut tube made up of?

Answer 3

endoderm

Question 4

Splanchnic mesoderm is the …. of the gut tube

Answer 4

covering

Question 5

The primitive gut tube has two bind endings and opens at what?

Answer 5

Umbilicus

Question 6

Which areas of gut start off as blind endings of the gut tube?

Answer 6

fore and hind gut

Question 7

What is the midgut continuous with?

Answer 7

Yolk sac

Question 8

List the foregut structures

Answer 8

Oesophagus, stomach, pancreas, liver, gall bladder and duodenum to the bile duct entry point

Question 9

Distal duodenum to the proximal 2/3 of transverse colon equates to which gut structures?

Answer 9

Midgut

Question 10

List the hind gut structures.

Answer 10

Distal 1/3 transverse colon, descending colon, sigmoid colon, rectum, upper anal canal and the inner lining of the urethra and bladder

Question 11

The celiac trunk supplies blood to the what structures?

Answer 11

foregut

Question 12

The superior mesenteric artery supplies …

Answer 12

the mid gut

Question 13

The hind gut is supplied by which artery?

Answer 13

Inferior mesenteric artery

Question 14

Each embryonic segment of the GI tract gets blood from distinct branches of the…..

Answer 14

abdominal aorta

Question 15

Which areas of the gut have a mixed blood supply and don’t follow the embryological segment rules?

Answer 15

Duodenum proximal to distal- coeliac to superior mesenteric
Head of pancreas coeliac turn
and the superior mesenteric artery

Question 16

What is the intraembryonic coelom?

Answer 16

The abdomen and thorax start as one large cavity in embryo folding, it later subdivides with the formation of the diaphragm. This cavity is somatic and splanchnic mesoderm sac.

Question 17

What is the significance of the intraembryonic coelom and its membrane?

Answer 17

One membrane lines the whole cavity and will later specialise in to the serousa to the different systems.

Question 18

What is a mesentery?

Answer 18

Double layer of peritoneum suspending the gut tube from the abdominal wall which allows a conduit for neuromuscular supply to the gut and allows some gut mobility.

Question 19

What mesoderm forms the peritoneum?

Answer 19

Visceral- splanchnic mesoderm

Parietal- somatic

Question 20

Which area of the gut has a ventral mesentry?

Answer 20

foregut

Question 21

Where do dorsal mesenteries exist?

Answer 21

Foregut, midgut and hind gut

Question 22

The dorsal and ventral mesenteries divide the cavity into left and right at the level of the foregut. What does the left sac become and what does the right sac become?

Answer 22

Left - greater sac

Right- lesser sac which will sit behind the stomach

Question 23

What are the omenta?

Answer 23

Specialised regions of peritoneum

Question 24

The dorsal mesentry froms the …. omentum and is the first structure seen in the abdominal cavity when approached anteriorly.

Answer 24

greater

Question 25

What is the lesser omenta?

Answer 25

Ventral mesentery with a free edge that conducts the portal triad. It runs from the stomach to the liver

Question 26

What structure rotates in development giving rise to the greater and lesser sacs as well as the omenta?

Answer 26

the stomach

Question 27

What is a peritoneal reflection?

Answer 27

A change in direction o the peritoneum - partial peritoneum to mesentery or from visceral peritoneum to mesentery

Question 28

What is a retroperitoneal organ?

Answer 28

Structures not suspended within the abdominal cavity, they do not have a mesentery

Question 29

Whats is the difference between a true retroperitoneal structure and a secondarily retroperitoneal structure?

Answer 29

True- never had a mesentery and where never enveloped by peritoneum. Secondary- began development invested by peritoneum but with gowth and development lost the mesentery by fusion with the posterior abdominal wall.

Question 30

What is the lung bud?

Answer 30

In the 4th week the respiratory diverticulum forms at the point of the pharyngeal guts ventral wall

Question 31

Which two buds does the forgeut extend between?

Answer 31

The lung bud and the liver bud

Question 32

What septum forms to separate the resp and GI tracts?

Answer 32

tracheoesophageal septum

Question 33

What is the frequency of oesophageal congenital defects from abnormal tracheoesophageal septum positioning?

Answer 33

1/3000

Question 34

Which mesentery forms the liver and binary tree?

Answer 34

ventral mesentry

Question 35

The pancreas forms when two things fuse in stomach rotation. Which two things fuse?

Answer 35

Ucinate process and inferior head ventrally | The superior head, neck body and tail dorsally

Question 36

In the 6th week the peritoneal reflections around the liver form what structures?

Answer 36

Lesser omentum falciform ligament And there is a bare area

Question 37

What developmental process leads to the c shape of the duodenum?

Answer 37

Stomach rotation pushes the duodenum right and then posteriorly which makes it retroperitoneal

Question 38

What is fusion fascia?

Answer 38

The point where mesentery of secondarily retroperitoneal structures was lost.

Question 39

Which foregut structures are secondarily retroperitoneal ?

Answer 39

Duodenum (except the cap) | Pancreas

Question 40

In which week is there a distal foregut dilation that indicates the position of the future stomach?

Answer 40

4th (mid week)

Question 41

Which border of the early dilation will give the greater curve?

Answer 41

dorsal border

Question 42

Is the lesser sac infant or behind the stomach?

Answer 42

behind