blastoderm

[blas-tuh-durm]

noun

Embryology.

1. the primitive layer of cells that results from the segmentation of the ovum.

2. the layer of cells forming the wall of the blastula, and in most vertebrates enclosing a cavity or a yolk mass.

blastoderm

/ ˈblæstəʊˌdɜːm /

noun

1. the layer of cells that surrounds the blastocoel of a blastula

2. a flat disc of cells formed after cleavage in a heavily yolked egg, such as a bird's egg

Other Word Forms

• blastodermic adjective
• blastodermatic adjective

Word History and Origins

Origin of blastoderm¹

First recorded in 1855–60; blasto- + -derm

Example Sentences

The embryo of a moth, a dragon-fly or a bug is invaginated into the yolk at the head end, the portion of the blastoderm necessarily pushed in with it forming the amnion.

From Project Gutenberg

That stage in the development of the ovum in which the outer cells of the morula become more defined and form the blastoderm.

From Project Gutenberg

Other writers hold that there is originally one primitive trace, and that composite terata are the product of a more or less extensive cleavage of this single blastoderm.

From Project Gutenberg

The rudimentary thorax presents traces of a division into three segments; and the dorso-lateral margins of the cephalic blastoderm, behind the procephalic lobes, have a sinuous margin.

From Project Gutenberg

"Sure," said the blastoderm, and they went apart, each to his dunnage kit.

From Project Gutenberg