Medical Dictionary


noun gas·tru·la \ˈgas-trə-lə\
plural gas·tru·las or gas·tru·lae \-ˌlē, -ˌlī\

Definition of GASTRULA

:  an early metazoan embryo in which the ectoderm, mesoderm, and endoderm are established either by invagination of the blastula (as in fish and amphibians) to form a multilayered cellular cup with a blastopore opening into the archenteron or (as in reptiles, birds, and mammals) by differentiation of the upper layer of the blastodisc into the ectoderm and the lower layer into the endoderm and by the inward migration of cells through the primitive streak to form the mesoderm—compare morula
gas·tru·lar \-lər\ adjective
March 29, 2015
discomfit Hear it
To thwart or disconcert
Take a 3-minute break and test your skills!
How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears