Hatching human blastocyst

The human pre-implantation embryo is composed of pluripotent cells that have the potential to form any cell of the body, and cells that will also form the placenta. After . ve days, the human blastocyst hatches from the thick glycoprotein matrix called the zona pellucida. The hatched blastocyst shown here was donated to research, and was photographed while growing out of its zona pellucida onto a supporting cell layer in a culture dish. Under these in vitro conditions, this blastocyst has the potential to generate a self-renewing human embryonic stem cell line.