Nodes of Ranvier are present in

Options

A. Non-myelinated neurons
B. Myelinated neurons
C. Non-medullated fibres
D. Both (1) and (2)

Answer

To solve the question "Nodes of Ranvier are present in," we will analyze the options provided and understand the structure of neurons.

### Step-by-Step Solution:

1. **Understanding Neurons**: Neurons are the basic structural and functional units of the nervous system. They can be classified based on the presence or absence of a myelin sheath.

2. **Myelinated Neurons**: Myelinated neurons have a myelin sheath, which is a lipid-rich membrane that insulates the axon. This myelin sheath is formed by Schwann cells that wrap around the axon.

3. **Nodes of Ranvier**: The nodes of Ranvier are small gaps in the myelin sheath where the axon is exposed. These nodes are crucial for the rapid conduction of nerve impulses through a process called saltatory conduction.

4. **Non-Myelinated Neurons**: Non-myelinated neurons do not have a myelin sheath. As a result, they do not have nodes of Ranvier, since there are no gaps in the myelin (as it is absent).

5. **Evaluating the Options**:
- **Non-myelinated neurons**: Incorrect, as they do not have nodes of Ranvier.
- **Myelinated neurons**: Correct, as they contain nodes of Ranvier.
- **Non-medulated fibers**: This term is likely a misspelling or misinterpretation of non-myelinated fibers, which also do not have nodes of Ranvier.
- **Both 1 and 2**: Incorrect, since only myelinated neurons have nodes of Ranvier.

6. **Conclusion**: The correct answer is that nodes of Ranvier are present in **myelinated neurons**.

### Final Answer:
**Myelinated neurons**

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