Which of the following statement is correct for node of Ranvier of nerve ?

Options

A. Neurilemma is discontinuous
B. Myelin sheath is discontinuous
C. Both neurilemma & myelin sheath are discontinuose
D. Covered by myelin sheath

Answer

To determine the correct statement regarding the node of Ranvier in a nerve, we can analyze each option provided. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Node of Ranvier
The node of Ranvier is a small gap in the myelin sheath of a nerve fiber. It plays a crucial role in the conduction of nerve impulses.

### Step 2: Evaluate Each Option
1. **Neuralema is Discontinuous**: This statement is incorrect. The neuralema (or neurilemma) is the outermost layer of the Schwann cells and is continuous along the nerve fiber.

2. **Myelin Sheath is Discontinuous**: This statement is correct. The myelin sheath is indeed discontinuous at the nodes of Ranvier, allowing for saltatory conduction of nerve impulses.

3. **Both Neuralema and Myelin Sheath are Discontinuous**: This statement is incorrect. While the myelin sheath is discontinuous, the neuralema is continuous.

4. **Covered by the Myelin Sheath**: This statement is incorrect as the node of Ranvier itself is the gap between segments of the myelin sheath.

### Step 3: Conclusion
Based on the evaluation of the options, the correct statement regarding the node of Ranvier is that the **myelin sheath is discontinuous**.

### Final Answer
The correct answer is option 2: **Myelin sheath is discontinuous.**

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