| blastocyte | An undifferentiated blastomere of the morula or blastula stage of an embryo. Origin: blasto-+ G. Kytos, cell (05 Mar 2000) |
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| blastocytoma | <tumour> A neoplasm composed chiefly or entirely of immature undifferentiated cells (i.e., blast forms), with little or virtually no stroma. Synonym: blastocytoma, embryonal carcinosarcoma. Origin: blasto-+ G. -oma, tumour (05 Mar 2000) |
| blastoderm | In many eggs with a large amount of yolk, cell division (cleavage) is restricted to a superficial layer of the fertilized egg (meroblastic cleavage). This layer is termed the blastoderm. In birds it is a flat disc of cells at one pole of the egg and in insects an outer layer of cells surrounding the yolk mass. (18 Nov 1997) |
| blastodermal | Relating to the blastoderm. (05 Mar 2000) |
| blastodermic disk | The aggregation of blastomeres of a telolecithal ovum after cleavage has occurred. (05 Mar 2000) |
| blastodermic ectoderm | External layer of the blastula. (05 Mar 2000) |
| blastodermic layers | The primordial cell layer's on the yolk surface of a telolecithal egg; in the earliest stages they consist of protoderm, and they later differentiate into ectoderm, endoderm, and mesoderm. (05 Mar 2000) |
| blastodermic vesicle | In mammalian development, cleavage produces a thin walled hollow sphere, whose wall is the trophoblast, with the embryo proper being represented by a mass of cells at one side. The blastocyst is formed before implantation and is equivalent to the blastula. (18 Nov 1997) |
| blastodisk | 1. The disk of active cytoplasm at the animal pole of a telolecithal egg. 2. The blastoderm, especially in very young stages when its extent is small. (05 Mar 2000) |
| blastogenesis | <biology> Multiplication or increase by gemmation or budding. Origin: Gr. Sprout + E. Genesis. Source: Websters Dictionary (01 Mar 1998) |
| blastogenic | Relating to blastogenesis. (05 Mar 2000) |
| blastoid | <zoology> One of the Blastoidea. Source: Websters Dictionary (01 Mar 1998) |
| blastoidea | <zoology> One of the divisions of Crinoidea found fossil in paleozoic rocks; pentremites. They are so named on account of their budlike form. Origin: NL, fr. Gr. Sprout. Source: Websters Dictionary (01 Mar 1998) |
| blastolysis | Dissolution or destruction of the blastocyst or blast cells and subsequent death. Origin: blasto-+ G. Lysis, loosening (05 Mar 2000) |
| blastolytic | Relating to blastolysis. (05 Mar 2000) |