blastula

n. (Embryology) cavity surrounded by a single layer of cells (first stage in the life of an embryo)

The blastula is an early stage of embryonic development in animals. It is also called blastosphere. It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells surrounding a central fluid-filled cavity called the blastocoel. The blastula follows the morula and precedes the gastrula in the developmental sequence.
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n. blastula, cavity surrounded by a single layer of cells (Embryology)

n. blastosphere, (Embryology) blastula, cavity surrounded by a single layer of cells (first stage in the life of an embryo)

n. blastula, (Embryology) cavity surrounded by a single layer of cells (first stage in the life of an embryo)