blastocyst

American  

[blas-tuh-sist] / ˈblæs tə sɪst /

noun

Embryology.

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

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blastocyst British  

/ ˈblæstəʊˌsɪst /

noun

1. Also called: blastosphere.  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

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blastocyst Scientific  

/ 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.

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Etymology

Origin of blastocyst

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

Compare meaning

How does blastocyst compare to similar and commonly confused words? Explore the most common comparisons:

• blastula vs. blastocyst

Example Sentences

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

From Science Daily • Mar. 23, 2024

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 • Feb. 21, 2024

What about preimplantation models of human embryos that mimic the blastocyst stage of natural embryos—that is, the stage at which doctors transfer fertility-clinic embryos into a patient’s uterus?

From Scientific American • Jul. 13, 2023

They’ve mimicked the blastocyst, the simple developmental stage that implants in the uterus, and recreated gastrulation, when embryos become multilayered.

From Science Magazine • Aug. 2, 2022

Figure 34.22 The rearrangement of the cells in the mammalian blastula to two layers—the inner cell mass and the trophoblast—results in the formation of the blastocyst.

From Textbooks • Jun. 9, 2022