blastocyst

[ blas-tuh-sist ]

noun

, Embryology.

1. the blastula of the mammalian embryo, consisting of an inner cell mass, a cavity, and an outer layer, the trophoblast.

blastocyst

/ ˈblæstəʊˌsɪst /

noun

1. Also calledblastosphere the blastula of mammals: a sphere of cells ( trophoblast ) enclosing an inner mass of cells and a fluid-filled cavity ( blastocoel )
2. See germinal vesicle
   another name for germinal vesicle

blastocyst

/ blăs′tə-sĭst′ /

1. The modified blastula that is characteristic of placental mammals. It has an outer layer, known as a trophoblast , that participates in the development of the placenta. The inner layer of cells develops into the embryo.

Word History and Origins

Origin of blastocyst¹

First recorded in 1885–90; blasto- + -cyst

Example Sentences

A research team based in Australia and Italy described animal experiments in which 1 in 4 vitrified cow eggs were fertilized and later grew, by around day 5, to the blastocyst stage.

From Science News

Back in 2018, a team grew similar blastocysts from mouse stem cells—an admirable effort, but not a perfect model as mice and humans have different development trajectories.

From Singularity Hub 

Scientists know that during a pregnancy, a fertilized egg develops into a blastocyst around day four, and it then implants around day eight.

From Singularity Hub 

Though they didn’t get beyond the blastocyst stage, both models are by far the most complete replicas of an early human embryo to date.

From Singularity Hub 

For instance, last week, Zernicka-Goetz posted a preprint describing how her lab coaxed stem cells to self-assemble into a version of a human blastocyst, as a week-old embryo is known.

From MIT Technology Review