what are embryo stem cells
Human embryonic stem cells in cell culture. Pluripotent: Embryonic stem cells are able to develop into any type of cell, excepting those of the placenta. Only embryonic stem cells of the morula are totipotent: able to develop into any type of cell, including those of the placenta. Embryonic stem cells (ES cells) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage preimplantation embryo. Human embryos reach the blastocyst stage 4â5 days post fertilization, at which time they consist of 50â150 cells.