LEC 14: Embryology III - 08.26.14 Flashcards Preview

STRUCTURES - WEEK 2 > LEC 14: Embryology III - 08.26.14 > Flashcards

Flashcards in LEC 14: Embryology III - 08.26.14 Deck (8):
1

gastrulation

formative process by which the three (3) germ layers and axial orientation are established in embryos

2

When does gastrulation begin

Gastrulation begins with the formation of the primitive streak at the beginning of week 3

3

Primitive Streak

  • epiblasts proliferate and migrate medially
  • Elongates cranially
  • epiblasts invaginate to form primitive node (at cranial portion of streak) and primitive groove

 

4

What is the significance of the primitive streak

  • determines cranial-caudal axis of embryo
  • formation of mesenchyme (embryonic mesoderm)

 

5

mesenchyme

same thing as embryonic mesoderm; formed by migration of epiblasts from primitive streak (groove) to become embryonic mesoderm

6

formation of embryonic endoderm during gastrulation

migrating cells of primitive streak will also push hypoblasts out of the way to form embryonic endoderm

7

When does primitive streak degenerate

Primitive streak degenerates by the end of week 4; cells of epiblast (through process of gastrulation) give rise to all 3 germ layers of embryo

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