Endoderm Development

Question 1

What does the endoderm form? (10 things)

Answer 1

• Pharynx
• Liver
• Urethra
• Prostate (males)
• Lungs**
• Trachea
• Gut
• Pancreas
• Pharyngeal pouches
• Bladder

Question 2

What 2 critical tubes does the endoderm develop?

Answer 2

1. The digestive tube
   - also the origin of the gallbladder, liver and pancreas
2. Respiratory tube

Question 3

What are the 4 pharyngeal pouches? (important)

Answer 3

1. Auditory canal for inner ear
2. Tonsils
3. Thymus and inferior parathyroid
4. Superparathyroid

Question 4

What is a diverticulum?

Answer 4

A sac or pouch branching from the main tube

Question 5

What is necessary for the specification and the differentiation of endodermal organs?

Answer 5

Reciprocal inductive interactions with the surrounding splanchnic lateral mesoderm

Question 6

Is the thyroid derived from a pouch?

Answer 6

No, but it is from the endoderm and it migrates posteriorly

Question 7

How is the respiratory tube initially formed?

Answer 7

It forms from a bud from the gut tube

Question 8

How does branching occur in lung formation?

Answer 8

1. FGF10 originally is expressed at the tip of the bud to promote growth.
2. Sprouty2 is then expressed and inhibits FGF10 in the middle of the tips to prevent the branch from getting too long
3. FGF10 continues to create two new buds now