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Atlas of Human Embryos Chapter   Figure

amniotic cavity, embryonic ectoderm, primitive node, umbilical vesicle cavity

A section through the primitive knot.

Observe:
1. The knot has not yet produced a noticeable localized elevation of the ectoderm.
2. The knot is caused by a rearrangement of cells in the middle of the ectoderm.


Keywords: amniotic cavity, embryonic ectoderm, primitive node, umbilical vesicle cavity

Source: Atlas of Human Embryos.