Cross striations seen in skeletal muscles are due to

Options

A. Difference in physiological function of various parts of muscle fibres
B. Difference in refractive indices
C. Difference in refractive property
D. Difference in conduction property of various parts of muscle fibre

Answer

To answer the question "Cross striations seen in skeletal muscles are due to," we will analyze the options provided and arrive at the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding Cross Striations**: Cross striations in skeletal muscles are visible bands that appear when observing muscle fibers under a microscope. These striations are a characteristic feature of striated muscles, which include skeletal and cardiac muscles.

2. **Analyzing the Options**:
- **Option 1**: Difference in the physiological function of various parts of muscle fibers.
- This option is incorrect because cross striations are not related to the physiological functions of the muscle fibers.

- **Option 2**: Differences in the refractive indices.
- This option is correct. Cross striations are due to the differences in the refractive indices of the various components of the muscle fibers. When light passes through these fibers, it bends at different rates due to the varying densities and structures, creating the appearance of striations.

- **Option 3**: Difference in the refractive property.
- This option is also incorrect. While it mentions refractive properties, it does not specifically address the differences in refractive indices which are crucial for the formation of striations.

- **Option 4**: Difference in the conductive property of various parts of the muscle fiber.
- This option is incorrect as well. Conductive properties do not relate to the appearance of cross striations.

3. **Conclusion**: After evaluating all options, the correct answer is **Option 2: Differences in the refractive indices**.