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n. pl. blas·tu·las or blas·tu·lae (-lē′)
An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity. Also called blastosphere.

[New Latin : from Greek blastos, bud + Latin -ula, feminine diminutive suff.]

blas′tu·lar adj.
blas′tu·la′tion (-lā′shən) n.


(Biology) embryol the process of blastula formation
References in periodicals archive ?
Both genomic DNA and mitochondrial DNA in spent medium were significantly correlated with fragmentation rate, one of the morphologic parameters conventionally used for assessing embryo quality, and mitochondrial DNA mirrored the blastulation potential of both fragmented and high-grade embryos.
Therefore, high ammonia in the culture media at the time of compaction and blastulation may reduce the availability of ATP for embryonic cells during a stage of development when energy demands by the embryo are high, resulting in increased degenerate ova and decreased blastocyst stages.
If blastulation occurred by late afternoon on day 5, fresh embryo transfer was performed on day 6; otherwise, blastocysts were vitrified and transferred the next cycle.
Accordingly, in early embryo the first and fourth cell cycles were prolonged by 4-5 h in the absence of serum during IVM-IVF, whereas the presence of serum during embryo culture decreased the duration of the fourth cell cycle leading to premature blastulation (12).