Development of GI tract

Question 1

In which week does the embryo fold laterally and craniocaudally?

Answer 1

4th week

Question 2

What are the structures in Foregut, midgut and hindgut?

Answer 2

foregut: oesophagus to duodenum (proximal to bile duct entrance), midgut: duodenum (distal to bile duct entrance) to proximal 2/3 transverse colon, hindgut: distal 1/3 transverse colon to internal lining of bladder and urethra

Question 3

What is the blood supply to the foregut?

Answer 3

Celiac trunk

Question 4

What is the blood supply to the midgut?

Answer 4

Superior mesenteric artery

Question 5

What is the blood supply to the hindgut?

Answer 5

Inferior mesenteric artery

Question 6

What is the intraembryonic coelom?

Answer 6

One large cavity in the embryo that later becomes the abdominal and thoracic cavities

Question 7

which part of the gut does the ventral mesentery line?

Answer 7

Foregut ONLY

Question 8

Where is the greater and lesser sac?

Answer 8

Greater sac is in front of the stomach, the lesser sac is behind the stomach

Question 9

What forms the greater omentum?

Answer 9

specialised region of peritoneum formed from dorsal mesentery

Question 10

What forms the lesser omentum?

Answer 10

specialised region of peritoneum formed from ventral mesentery

Question 11

What is the difference between retroperitoneal and secondarily retroperitoneal?

Answer 11

retroperitoneal : were never in the peritoneal cavity and never had a mesentery. Secondarily retroperitoneal : initially invested by peritoneum and had a mesentery but loses this with development

Question 12

Name the ligament that separates the left and right lobe of the liver

Answer 12

Falciform ligament

Question 13

Name 2 secondarily retroperitoneal structures of the foregut

Answer 13

duodenum and pancreas

Question 14

Why does the midgut leave the abdomen in development?

Answer 14

The cavity becomes too small due to rapid growth of the liver

Question 15

Which structure acts as the axis for the rotation of the primary intestinal loop?

Answer 15

Superior mesenteric artery

Question 16

How much does the midgut rotate?

Answer 16

270 degrees anticlockwise

Question 17

Name 2 complications of rotation

Answer 17

Incomplete rotation (Left-sided colon) and reversed rotation (transverse colon posterior to duodenum)

Question 18

Name 2 complications with volvulus

Answer 18

Strangulation and Ischaemia

Question 19

What is the name of the structure that connects the primary intestinal loop to the yolk sac?

Answer 19

Vitelline duct

Question 20

What is the most common remenant of the vitelline duct?

Answer 20

Meckel’s diverticulum

Question 21

Define recanalisation

Answer 21

Cell growth is so rapid that the lumen of the gut tube closes, recanalisation re-opens the tube

Question 22

What results if recanalisation is unsuccessful?

Answer 22

Atresia or stenosis

Question 23

Define Pyloric stenosis

Answer 23

Hypertrophy of the circular muscle in the region of the pyloric sphincter causing projectile vomiting

Question 24

Which 2 distinct structures form the anal canal?

Answer 24

Proctodeum and the cloaca

Question 25

What is the lymphatic drainage above and below the pectinate line in the anal canal?

Answer 25

Above = Internal iliac nodes, Below = Superficial inguinal nodes

Question 26

Name 2 hindgut abnormalities

Answer 26

Imperforate anus and Hindgut fistulae