L13: Branching Morphogenesis 2

Question 1

From what do the 2 primary lung buds form?

Answer 1

forgut

Question 2

What is essential for 2 primary lung buds from forgut?

Answer 2

FGF10

Question 3

During lunch development, which two molecules are in abundance?

Answer 3

sox9 and E-cadherins

Question 4

How many generations in lung development unlike trachea development?

Answer 4

23

Question 5

What primary mechanism leads to branching in lungs?

Answer 5

Bud bifurcation

Question 6

Is mesenchyme essential to bifurcation?

Answer 6

Yes. Without mesenchyme on buckling occurs. No branching

Question 7

Is FGF essential to branching?

Answer 7

No. FGF only promotes cell migration. But no branching

Question 8

What experiment showed FGF is not essential to branching in lung?

Answer 8

Bead soaked in FGF didn’t promote branching to bud piece.

Question 9

What is essential for bifurcation in lung buds?

Answer 9

airway smooth muscles

Question 10

How long before bifurcation does smooth muscles appear?

Answer 10

~10

Question 11

At which points do smooth muscles contract around the bud?

Answer 11

stem and neck

Question 12

How many hours does bifurcation with smooth muscles take?

Answer 12

~24 hours

Question 13

Does speeding up or slowing SMA development down change bifurcation?

Answer 13

Yes.
Faster development. No branching or cleft.
Inhibited growth. No branching. But cleft is formed.