Animal pole

In developmental biology, the term animal pole refers to the upper hemisphere of a blastula embryo (as it is conventionally drawn, in reality the animal pole may not be the upper hemisphere). The animal pole consists of small cells that divide rapidly, in contrast with the vegetal pole below it. The animal pole draws its name from its liveliness relative to the slowly-developing vegetal pole. In some cases, the animal pole is thought to differentiate into the later embryo itself, forming the three primary germ layers and participating in gastrulation.