Plate 15
|
PLATE NUMBER |
STAGE |
TIME |
ORIENTATION |
IMAGE |
|
15 |
Early gastrula Embryo stage 10+ |
10 h p.f. |
Animal Ventral Vegetal |
Sagittal section |
Dorsal
Onset of Gastrulation stage (Embryo stage 10+)
The roof of the blastocoel consits of two cell layers; an outer epithelial cell layer and an inner sensorial layer. The constant epibolic movements of cells takes place more dorsally rather than vegetally with the sub-epithelial layer of cells as well as the cells of the deep zone moving toward the animal pole. The boundary between the involuting marginal zone (IMZ) and non-involuting marginal zone (NIMZ) is not as clear as shown diagrammatically and is hard to detect.