The gray matter differs from white matter in the :

Options

A. Absence of axons
B. Absence of myelin sheath
C. Presence of myelin sheath
D. Absence of nurilemma

Answer

To answer the question about how gray matter differs from white matter, we can follow these steps:

### Step 1: Understand the Composition of Gray Matter
Gray matter primarily consists of neuronal cell bodies, dendrites, and unmyelinated axons. It is where most of the synaptic connections occur in the brain and spinal cord.

**Hint:** Think about what types of cells and structures are found in gray matter.

### Step 2: Understand the Composition of White Matter
White matter, on the other hand, is composed mainly of myelinated axons. The myelin sheath is a fatty layer that insulates the axons and facilitates faster transmission of electrical signals.

**Hint:** Consider what gives white matter its characteristic color and how it functions in the nervous system.

### Step 3: Analyze the Options
1. **Absence of Axons**: This is incorrect because gray matter does contain some axons, albeit fewer than white matter.

2. **Absence of Myelin Sheath**: This is correct. Gray matter has very little myelinated axons, indicating a lack of myelin sheath compared to white matter.

3. **Presence of Myelin Sheath**: This is incorrect because white matter is characterized by the presence of myelin sheaths around its axons.

4. **Absence of Neurolemma**: This is incorrect as well. Neurolemma (or neurilemma) is present in both types of matter, serving to protect peripheral nerve fibers.

### Step 4: Conclusion
Based on the analysis, the correct answer to the question is that gray matter differs from white matter in the **absence of the myelin sheath**.

**Final Answer:** The gray matter differs from white matter in the absence of the myelin sheath.

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