Online Encyclopedia
Blastocyst
A blastocyst is an embryo at a stage where it consists of 30-150 cells. It is covered in a layer of trophoblasts, cells which will eventually form the placenta. The inner cells of the blastocyst are undifferentiated, and a source of embryonic stem cells.
Last updated: 02-18-2005 13:43:04
Last updated: 03-13-2005 10:38:26