Myelin sheath is produced by:

Options

A. Schwann cells and oligo dendrocytes
B. Astrocytes and schwann cells
C. Oligodendrocytes and osteoclasts
D. Osteoclasts and Astrocytes

Answer

**Step-by-Step Solution:**

1. **Understanding Myelin Sheath**: The myelin sheath is an insulating layer that surrounds nerve fibers, including those in the brain and spinal cord. It is composed of protein and fatty substances and plays a crucial role in the rapid transmission of electrical impulses along nerve cells.

2. **Identifying the Cells that Produce Myelin Sheath**: The question asks which cells are responsible for producing the myelin sheath. The options provided include different types of cells.

3. **Evaluating the Options**:
- **First Option**: Schwann cells and oligodendrocytes.
- **Schwann Cells**: These are the primary glial cells in the peripheral nervous system that form the myelin sheath around peripheral nerves.
- **Oligodendrocytes**: These are large glial cells in the central nervous system that also produce myelin sheath.
- **Conclusion**: This option is correct because both Schwann cells and oligodendrocytes are involved in the formation of the myelin sheath.

- **Second Option**: Astrocytes and Schwann cells.
- **Astrocytes**: These cells are involved in maintaining the blood-brain barrier and do not produce myelin.
- **Conclusion**: This option is incorrect because astrocytes do not contribute to the formation of the myelin sheath.

- **Third Option**: Oligodendrocytes and osteoclasts.
- **Osteoclasts**: These are bone cells that break down bone tissue and are not involved in myelin production.
- **Conclusion**: This option is incorrect because while oligodendrocytes produce myelin, osteoclasts do not.

- **Fourth Option**: Astrocytes and osteoclasts.
- **Conclusion**: This option is also incorrect as neither astrocytes nor osteoclasts produce myelin.

4. **Final Conclusion**: The correct answer is the first option: Schwann cells and oligodendrocytes, as both types of cells are responsible for the production of the myelin sheath.