The key difference between archenteron and blastocoel is that archenteron is the primary gut formed during gastrulation in the developing zygote, which later develops into the digestive tube, while blastocoel is an inner fluid-filled or yolk-filled cavity of the blastula formed during blastulation.
Fertilization is the event of sexual reproduction that forms a diploid zygote. The zygote eventually turns into an embryo. The embryo undergoes mitotic divisions and cellular differentiation, making a multicellular embryo. Morula is an early stage of the embryo, which contains 16 cells. Morula becomes the blastula at the seventh cleavage. Blastula contains 128 cells. It is a hollow sphere of cells surrounding an inner fluid-filled cavity. And, this fluid-filled cavity of blastula is known as blastocoel. Blastula folds inwards and enlarges to make gastrula, which is a multilayered structure containing primary germ layers. Archenteron is the primary gut located in the gastrula. Archenteron develops into the digestive tube later.
