Odd one out w.r.t. origin

Options

A. Astrocyte
B. Microglial cells
C. Oligodendrocytes
D. Ependymal cells

Answer

To solve the question "Odd one out with respect to origin," we need to analyze the origins of the given cell types: astrocytes, microglial cells, oligodendrocytes, and ependymal cells.

### Step-by-Step Solution:

1. **Identify the Cell Types**: The options provided are:
- Astrocytes
- Microglial cells
- Oligodendrocytes
- Ependymal cells

2. **Understand the Origin of Nervous Tissue**:
- Nervous tissue originates from the ectoderm during embryonic development.
- The two main categories of cells in nervous tissue are neurons and neuroglial cells (glial cells).

3. **Determine the Origin of Each Cell Type**:
- **Astrocytes**: These are neuroglial cells that originate from the ectoderm.
- **Oligodendrocytes**: These also originate from the ectoderm.
- **Ependymal Cells**: These cells line the ventricles of the brain and the central canal of the spinal cord, and they too originate from the ectoderm.
- **Microglial Cells**: Unlike the others, microglial cells originate from the mesoderm. They are considered resident macrophages of the central nervous system and play a role in immune defense.

4. **Identify the Odd One Out**:
- Since astrocytes, oligodendrocytes, and ependymal cells all originate from the ectoderm, and microglial cells originate from the mesoderm, the odd one out with respect to origin is **microglial cells**.

5. **Conclusion**: Therefore, the correct answer to the question is **microglial cells**.