blastoderm

American  

[blas-tuh-durm] / ˈblæs təˌdɜrm /

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 British  

/ 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

• blastodermatic adjective
• blastodermic adjective

Etymology

Origin of blastoderm

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

Example Sentences

Such words as "blastoderm", "sindoc," "peris," "parasang," "sarcenet," "teazel," "nullah," "cantatrice," "barracan," "sistrum," writhed and hissed in her verses.

From Time Magazine Archive

Blastem: a nucleated protoplasmic layer preceding the blastoderm.

From Explanation of Terms Used in Entomology by Smith, John. B.

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 On the Origin and Metamorphoses of Insects by Lubbock, John, Sir

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 Essays In Pastoral Medicine by ?Malley, Austin

It is characteristic of this kind of ovum that there is always a row of nuclei, called the yolk-nuclei, placed in the denser yolk immediately adjacent to the blastoderm.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various