Chapter 20: Endoderm Flashcards
What are the four pharyngeal arches and their derivatives?
1) auditory cavities in the middle ear
2) walls of tonsils
3) thymus and parathyroid
4) parathyroid glands
Which part of the heart is derived from endoderm?
pericardial coelom
What are the embryonic functions of endoderm?
1) Formation of the heart, blood vessels, notochord, and mesoderm
2) Form the lining of digestive tube and respiratory tube
3) Form the epithelium of several glands (tonsils, thymus, and parathyroid)
How are different endoderm progenitors patterned?
Using a scale of BMPs, FGFs, and Wnts to form the AFG, PG, MG-HG to specify progenitors
Nodal
The key molecule to endoderm specification
epiblast ->nodal-> mesendoderm-> nodal -> definitive endoderm
What does AFG turn into?
Low levels lead to the lung and thyroid
What does the MG-HG turn into?
High levels turn into the intestine
Digestive Tube
Extends the length of the body, buds form the liver, gallbladder and pancreas
What does PFG turn into?
Moderate levels turn into the pancreas
Pharynx
region of digestive tube anterior to the point where respiratory tube branches off
Respiratory Tube
forms an outgrowth of the digestive tube, and bifurcates into two lungs
Definitive endoderm
set of cells that enters the interior of embryo through the primitive streak
Visceral endoderm
primarily forming the yolk sac
anterior intestinal portal (AIP)
in the foregut, cells from the lateral portion of the anterior endoderm move ventrally to form the AIP
Caudal intestinal portal (CIP)
this forms from the posterior endoderm
