Question

Why the cells of the inner cell mass of blastocyst are called stem cells?

Answer 1

The embryo at 64 celled stage is known as blastocyst. It comprises of an inner cell mass which is attached to embryonic pole and an outer covering of cells which is known as trophoblast. The trophoblast later forms the chorion which is part of placenta. The inner cell mass has the property to undergo unlimited symmetrical divisions without getting differentiated. They can give rise to any tissue or organ of the body. Hence, inner cell mass of blastocyst are called stem cells because these are undifferentiated cells which have the capability to differentiate into specialised cells.