Blastocoel
The cavity in the blastula of the developing embryo.
Blastocyst
A preimplantation embryo of about 150 cells. The blastocyst consists of a sphere made up of an outer layer of cells (the trophectoderm), a fluid-filled cavity (the blastocoel), and a cluster of cells on the interior (the inner cell mass).
Bone marrow stromal cells
A stem cell found in bone marrow that generates bone, cartilage, fat, and fibrous connective tissue.