Figure 11.11. Migration of endodermal and mesodermal cells through the primitive streak.

Figure 11.11

Migration of endodermal and mesodermal cells through the primitive streak. (A) Scanning electron micrograph shows epiblast cells passing into the blastocoel and extending their apical ends to become bottle cells. (B) Stereogram of a gastrulating chick embryo, showing the relationship of the primitive streak, the migrating cells, and the two original layers of the blastoderm. The lower layer becomes a mosaic of hypoblast and endodermal cells; the hypoblast cells eventually sort out to form a layer beneath the endoderm and contribute to the yolk sac. (A from Solursh and Revel 1978, courtesy of M. Solursh; B after Balinsky 1975.)

From: Early Development in Birds

Cover of Developmental Biology
Developmental Biology. 6th edition.
Gilbert SF.
Sunderland (MA): Sinauer Associates; 2000.
Copyright © 2000, Sinauer Associates.

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