noun, plural blas·tu·las, blas·tu·lae [blas-chuh-lee] /ˈblæs tʃəˌli/. Embryology.
- the early developmental stage of an animal, following the morula stage and consisting of a single, spherical layer of cells enclosing a hollow, central cavity.
- embryol the process of blastula formation
noun plural -las or -lae (-liː)
- an early form of an animal embryo that develops from a morula, consisting of a sphere of cells with a central cavityAlso called: blastosphere
embryonic state, 1875, Modern Latin, from Greek blastos “sprout, germ” + diminutive ending -ula.
n. pl. blas•tu•las
- An early embryonic form produced by cleavage of a fertilized ovum and consisting of a spherical layer of cells surrounding a fluid-filled cavity.
Plural blastulas blastulae (blăs′chə-lē′)
- An animal embryo at the stage immediately following the division of the fertilized egg cell, consisting of a ball-shaped layer of cells around a fluid-filled cavity known as a blastocoel. Compare gastrula. See also blastocyst.
The stage of an embryo that consists of just over a hundred cells — a stage reached about one week after fertilization. At this stage the cells are just at the very beginning of cellular differentiation and are said to be totipotent (See totipotency).