Question

Study the following statements and identify the correct option :
Statement I : Satellite cells surround the cell bodies in ganglia of central nervous sytem.
Statement II : All types of neuroglial cells originate from the embryonic ectoderm.

• A. Both statement I and II are correct.
• B. Statement I is correct, but statement II is incorrect.
• C. Statement I is incorrect, but statement II is correct.
• D. Both statements I and II are incorrect.

Hint:

Remember the key distinction between CNS and PNS glial cells: Satellite cells are PNS glial cells. Also, be aware of the developmental origins of glial cells; microglia are unique in their mesodermal origin compared to other glial cells that are ectodermal.

Answer 1

The Correct Option is D

Step 1: Analyze Statement I.
Statement I: "Satellite cells surround the cell bodies in ganglia of central nervous sytem."
Satellite cells are indeed neuroglial cells that surround the cell bodies of neurons. However, they are primarily found in the ganglia of the peripheral nervous system (PNS), not the central nervous system (CNS). In the CNS, neuronal cell bodies are typically surrounded by astrocytes or other glial cells, but not specifically satellite cells. Therefore, Statement I is Incorrect. Step 2: Analyze Statement II.
Statement II: "All types of neuroglial cells originate from the embryonic ectoderm."
Neuroglial cells (or glial cells) are non-neuronal cells that support and protect neurons. While most neuroglial cells (like astrocytes, oligodendrocytes, and ependymal cells in the CNS, and Schwann cells in the PNS) do originate from the embryonic ectoderm (specifically, the neural tube or neural crest), there is a significant exception: microglia. Microglia are immune cells of the CNS and originate from the mesoderm (specifically, from hematopoietic stem cells in the yolk sac) rather than the ectoderm. Since the statement says "All types," and microglia are a type of neuroglial cell with a mesodermal origin, this statement is Incorrect. Step 3: Evaluate the options based on the truthfulness of Statement I and Statement II.
\begin{itemize} \item Option (1): Both statement I and II are correct. (Incorrect, as both are incorrect) \item Option (2): Statement I is correct, but statement II is incorrect. (Incorrect, as Statement I is also incorrect) \item Option (3): Statement I is incorrect, but statement II is correct. (Incorrect, as Statement II is also incorrect) \item Option (4): Both statements I and II are incorrect. (This matches our analysis) \end{itemize} Step 4: Conclude the correct option.
Based on the analysis, both Statement I and Statement II are incorrect. The final answer is $\boxed{\text{Both statements I and II are incorrect.}}$.