Embryo Development
Embryo development begins a few hours after fertilization. Typically, the first division starts approximately 16 hours after fertilization. The fertilized egg divides into two daughter cells called blastomeres.
On the 2nd day of life, the embryo normally consists of 2 or 4 blastomere cells.
On the 3rd day of life, the embryo normally consists of 5 to 8 blastomere cells.
The cellular stage of the embryo is followed by the morula stage. At this stage, the embryo consists of 16-32 cells, which form a compact mass. The morula stage is reached on the 4th day of development.
On the 5th day of development, the embryo reaches the blastocyst stage. At this stage, the embryo consists of 60-120 cells, which form two different groups of cells. An outer layer of cells, which will form the placenta and an inner mass of cells which will later form the embryo itself.
