Name the specialized cells found in human embryo that can give rise to all the tissues and organs.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Stem cells
The inner cell mass of the early embryo holds stem cells.
(1) Trophoblast — Incorrect. This is the outer layer of the blastocyst. It attaches to the uterine wall and forms the embryonic part of the placenta. It is not the source of all tissues.
(2) Stem cells — Correct. They can form all the tissues and organs.
(3) Blastomeres — Incorrect. These are the daughter cells made by the cleavage divisions of the zygote (2, 4, 8, 16 cells). They are not the specialised cells of the inner cell mass.
(4) Hepatocytes — Incorrect. These are the cells of the liver. They are already specialised.
NCERT Extract:
Pregnancy and Embryonic Development – “… Immediately after implantation, the inner cell mass (embryo) differentiates into an outer layer called ectoderm and an inner layer called endoderm. A mesoderm soon appears between the ectoderm and the endoderm. These three layers give rise to all tissues (organs) in adults. It needs to be mentioned here that the inner cell mass contains certain cells called stem cells which have the potency to give rise to all the tissues and organs.”