Organism at the blastula stage - an early stage of embryonic development in animals. It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells surrounding a central fluid-filled cavity called the blastocoel. The blastula follows the morula and precedes the gastrula in the developmental sequence.

http://upload.wikimedia.org/wikipedia/commons/c/c6/Blastulation.png

TODO - check relationship with epiblast. Note in FMA this is not a subclass of embryo, but in uberon embryo is the whole organism from zygote onwards and thus includes the blastula

blastula embryo

UBERON:0007011

uberon

blastosphere

UBERON:0000307

http://purl.obolibrary.org/obo/uberon.owl, http://purl.obolibrary.org/obo/cl.owl

• gastrula

• presumptive endoderm
• presumptive ectoderm
• presumptive mesoderm
• presumptive paraxial mesoderm
• blastocyst