GI tract

Question 1

When does GI tract development occur

Answer 1

3rd to 12th weeks embryonic age (5 to 14 weeks LMP)

Question 2

What occurs during GI tract development

Answer 2

Primary germ layer formation, gut tube formation, regionalised changes caused by rotation, swelling, elongation
Organs and glands produced by budding from the gut tube

Question 3

Describe primary germ layer formation

Answer 3

Gastrulation - Third week, embryo implanted into uterine wall, embryo is a flat disc, comprised of epiblast and hypoblast.

Primitive streak forms

Question 4

What is the mesoderm

Answer 4

Surrounding muscle, connective tissue and mesenteries

Question 5

What is the endoderm

Answer 5

EPithelium of the gut tube

Question 6

What is ectoderm

Answer 6

Innervation of the gut

Question 7

What does hypoblast give rise to

Answer 7

Extra-embryonic tissue

Question 8

Describe initial gut folding and tube formation

Answer 8

Gut tube is formed by folding of sheets of cells in two directions
Folding towards the midline along the cranial-caudal axis
Folding towards yolk sac at the cranial and caudal ends

Question 9

What are hox gene expression boundaries

Answer 9

Specify position of GI tract structures