Blastoderm
From Wikipedia, the free encyclopedia
A blastoderm (germinal disc, blastodisc), also called the cicatricula , is a single layer of embryonic epithelial tissue that makes up the blastula.[1] It encloses the fluid-filled blastocoel. Gastrulation follows blastoderm formation, where the tips of the blastoderm begins the formation of the ectoderm, mesoderm, and endoderm.[2]
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Formation
The blastoderm is formed when the oocyte plasma membrane begins cleaving by invagination, creating multiple cells that arrange themselves into an outer sleeve to the blastocoel.[1]
In oviparous animals
In chicken eggs, the blastoderm represents a flat disc after embryonic fertilization.[3] At the edge of the blastoderm is the site of active migration by most cells.[4]
DNA repair genes are highly expressed in chicken blastoderms.[5]