Question

Identify the structures which have the potency to give rise to all the tissues and organs.

• A. Stem cells
• B. Trophoblast
• C. Chorionic villi
• D. Placenta

Hint:

Embryonic Cell Types:
$\bullet$ Inner Cell Mass (ICM) Stem Cells: Pluripotent cells giving rise to all three germ layers and all body tissues/organs.
$\bullet$ Trophoblast: Forms extra-embryonic membranes and placenta.

Answer 1

The Correct Option is A

Concept:
During human embryonic development, cellular differentiation leads to the formation of specialized tissues and organs from pluripotent progenitor cells.

Step 1: Role and Potency of Stem Cells:
The blastocyst stage of embryonic development contains an outer cellular layer called the trophoblast and an inner group of cells attached to one pole called the inner cell mass (ICM).
The inner cell mass contains specialized, undifferentiated cells termed stem cells.
Stem cells possess pluripotency, which gives them the developmental capacity to differentiate into all the specialized embryonic germ layers (ectoderm, mesoderm, and endoderm) and subsequently form all tissues and organs of the adult organism.

Step 2: Evaluating the Alternative Structures:
- Trophoblast: The outer epithelial layer of the blastocyst that attaches to the endometrium and helps form extraembryonic membranes and the fetal portion of the placenta.
- Chorionic villi: Finger-like projections produced by the trophoblast that interdigitate with maternal uterine tissue to form the placenta.
- Placenta: The structural and functional organ facilitating nutrient, respiratory gas, and waste exchange between maternal and fetal blood.

Step 3: Conclusion:
The cells that possess the potency to give rise to all tissues and organs are Stem cells.