Zebrafish - Gastrula Period

The duration of this period is from 5.25 to 10.33 hours

• Transition from 50% epiboly to 1-4 somites

• Primary germ layers (also known as 'germ ring') are produced during this stage

• Each germ layer (endoderm, mesoderm, ectoderm) is put in the right place so that bodily organs and tissues can form in the correct locations

• Involution produces the germ ring by folding the blastoderm back upon itself

• Shield Stage occurs forming the dorsal side of the embryo sprouting pericardial regions.

• The Precordial plate within the animal pole forms the head structures

• The gastrula period ends when epiboly is complete, and the tail bud has form

Here, there is a large number of cell migrations occurring to make sure each germ layer (endoderm, mesoderm, ectoderm) is in the right place so that bodily organs and tissues can form in the correct location. The shield then forms marking the dorsal side of the embryo and forming the pericardial region ventrally from the head region to the tail region. The PreCordial plate here forms the head structures. Lastly the tail bud forms indicating the end of epiboly. Effectively the blastoderm has covered the entire yoke.

Zygote Period / Cleavage Period / Blastula Period / Segmentation Period / Pharyngula Period / Hatching Period / Larval Period] / Home Page