Epiboly describes one of the five major types of cell movements that occur in the gastrulation stage of embryonic development of some organisms.[1] Epiboly is the spreading and thinning of the ectoderm while the endoderm and mesoderm layers move to the inside of the embryo.[2]
When undergoing epiboly, a monolayer of cells must undergo a physical change in shape in order to spread. Alternatively, multiple layers of cells can also undergo epiboly as the position of cells is changed or the cell layers undergo intercalation. While human embryos do not experience epiboly, this movement can be studied in sea urchins, tunicates, amphibians, and most commonly zebrafish.
