Gastrulation

Illustration Description

The illustration is depicting the stages of ‘gastrulation’ which is a very important event during human, animal development. It is the part of the cell division where the ball of cells called the blastula, move to re-organise the embryo from a simple hollow ball of cells into a multilayered and multidimensional structure called the gastrula and it is where the bodily axes observed in the mature adult are created. The divisions are largely controlled by the primitive streak. The primitive streak is a groove in the midline of the epiblast (a single cell-layered epithelium) which appears during the third week. There are three cell layers that are responsible for forming the different tissues of the embryo.