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. 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

The technique, called blastocyst complementation, is similar to a technique used to create mice with human immune systems, which have proven to be powerful research tools.

From Science Daily

Prior to implantation, an embryo is a ball of about 250 cells organized as a blastocyst.

From Science Daily

A blastocyst is the early stage of an embryo, which is defined as the state of development that starts at fertilization and lasts up to eight weeks.

From Seattle Times

Some fertility centers freeze them one day after fertilization and some wait five or six days until they become blastocysts, which may be 200- to 300-cell organisms.

From Los Angeles Times

The investigators first established nine stem cell lines using cells removed from 7-day-old blastocyst embryos.

From Science Daily