Anatomy: gastrointestinal development

Question 1

Answer 1

Question 2

Contributions of each of the 3 germ layers to the GIT?

Answer 2

Endoderm: mucosal epithelium, mucosal/submucosal glands (epithelium)

Mesoderm: lamina propria, muscularis mucosae, submucosal connective tissue, blood vessels (muscle, connective tissue)

Neural crest: neurons and nerves of the submucosa (neural)

Question 3

Foregut

Answer 3

Question 4

Midgut

Answer 4

Question 5

Hindgut

Answer 5

Question 6

Foregut
- Does the foregut have both a ventral and dorsal mesentery?
- The stomach rotates during development, what happens to the vagus nerves?
- Is the oesophagus supplied by arteries other than the coeliac trunk?

Answer 6

• Yes
• The vagus nerves follow the rotation of the stomach; left becomes anterior, right becomes posterior
• Yes

Question 7

Midgut and hindgut
- Does the midgut and hindgut have dorsal and ventral mesentery?
- Does the midgut elongate, twist, invaginate out of the fetus, spin on several axes, and come back into the fetus as the small/parts of the large intestine?
- What phenomenon occurs when the primary intestinal loop sticks out of the abdominal cavity and into the umbilical cord?

Answer 7

• No, dorsal only
• Yes
• Physiological hernia

Question 8

What causes the mesentery to become more complex?

Answer 8

Gut tube, lengthens, enlarges, rotates on several axes during dev. These deformations/rotations are largely what takes simple dorsal/ventral mesenteries into more complicated things