| 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) |
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| 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) |
| bilaminar blastoderm | The blastoderm of a young embryo when it consists of only two of the three primary germ layers it will ultimately have. (05 Mar 2000) |
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| embryonic blastoderm | That part of the blastoderm that takes part in the formation of the embryonic body. (05 Mar 2000) |
| trilaminar blastoderm | The blastoderm after all three of the primary germ layers have been established. (05 Mar 2000) |
| extraembryonic blastoderm | That part of the blastoderm which is not incorporated in the embryo but forms membranes concerned in its nourishment and protection. (05 Mar 2000) |