Glial cells forming blood brain barrier are formed of

Options

A. Ranvier cells
B. Schwann cells
C. Astrocytes
D. Oligodendroglial cells.

Answer

**Step-by-Step Solution:**

1. **Understanding the Blood-Brain Barrier (BBB)**: The blood-brain barrier is a selective barrier that protects the brain from potentially harmful substances in the blood while allowing essential nutrients to pass through.

2. **Identifying the Role of Glial Cells**: Glial cells are non-neuronal cells in the nervous system that support and protect neurons. They play a crucial role in maintaining homeostasis, forming myelin, and providing support and protection for neurons.

3. **Types of Glial Cells**: There are several types of glial cells, including:
- **Astrocytes**: Star-shaped cells that provide structural support and help maintain the blood-brain barrier.
- **Oligodendrocytes**: Cells that insulate axons in the central nervous system.
- **Microglia**: Immune cells of the central nervous system that respond to injury and disease.
- **Schwann Cells**: Cells that form myelin sheaths around axons in the peripheral nervous system.

4. **Analyzing the Options**:
- **Cranial Cells**: Not a recognized type of glial cell.
- **Schwann Cells**: Involved in myelination in the peripheral nervous system, not the blood-brain barrier.
- **Astrocytes**: Known to contribute to the formation and maintenance of the blood-brain barrier.
- **Oligodendroglial Cells**: Primarily involved in insulating axons, not in forming the blood-brain barrier.

5. **Conclusion**: Based on the roles of the different types of glial cells, the correct answer to the question is **Astrocytes**.

**Final Answer**: Astrocytes

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