Tags: Anatomical Structure, Embryology.
The blastula (from Greek βλαστός (blastos) meaning sprout) is a hollow sphere of cells referred to as blastomeres surrounding an inner fluid-filled cavity called the blastocoele formed during an early stage of embryonic development in animals. Embryo development begins with a sperm fertilizing an egg to become a zygote which undergoes many cleavages to develop into a ball of cells called a morula. Only when the blastocoele is formed does the early embryo become a blastula.
