资料来源 : pyDict

胞胚

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Blastula \Blas"tu*la\, n. [NL., dim. of Gr. blasto`s a sprout.]
   (Biol.)
   That stage in the development of the ovum in which the outer
   cells of the morula become more defined and form the
   blastoderm.

资料来源 : WordNet®

blastula
     n : early stage of an embryo produced by cleavage of an ovum; a
         liquid-filled sphere whose wall is composed of a single
         layer of cells; during this stage (about eight days after
         fertilization) implantation in the wall of the uterus
         occurs [syn: {blastodermic vesicle}]
     [also: {blastulae} (pl)]