Lecture 12: Establishment of Body Plan II

Question 0

What is different anteriorly and posteriorly during initial endodermal formation?

Answer 0

Anteriorly: High levels of nodal
Posteriorly: Low levels of nodal & FGF-4

Question 1

What does the initial signaling of endoderm formation depend on?

Answer 1

Nodal

Question 2

What does the posterior gut express?

Answer 2

Cdx-2

Question 3

What does the anterior gut express?

Answer 3

Hex, Sox-2, & Foxa-2

Question 4

What are expressed in the anterior and posterior intestinal portals?

Answer 4

Anterior portal: Shh

Posterior portal: Shh followed by BMP-4

Question 5

Hoxa_____ helps with anterior formation and Hoxa_____ helps with posterior formation.

Answer 5

Hoxa-d9

Hoxa-d13

Question 6

What is the stomodeum and proctodeum?

Answer 6

Stomodeum: future oral cavity
Proctodeum: future anal region

Question 7

What are the major features of the 4th week embryo?

Answer 7

Beginning of major organ systems (except limbs and kidneys),

Wolffian ridge, & pharyngeal arches present