Which of the following statements about the striated muscle is incorrect

Options

A. In the centre of each I-band is an elastic (Z-line) which bisects it.
B. Thin filaments are firmly attached to the Z-line.
C. M-line is a fibrous membrane in the middle of A-bands.
D. none of these

Explanation

To determine which statement about striated muscle is incorrect, we need to analyze each provided statement based on our understanding of muscle structure and function. Here’s a step-by-step breakdown:

### Step 1: Understand the Structure of Striated Muscle
Striated muscles, also known as skeletal muscles, have a distinct appearance under a microscope due to alternating light and dark bands. This striation is caused by the arrangement of two main contractile proteins: actin and myosin.

### Step 2: Identify the Proteins Involved
- **Actin**: This is a thin filament and appears lighter in color. It is also referred to as the I band (isotropic band).
- **Myosin**: This is a thick filament and appears darker. It is referred to as the A band (anisotropic band).

### Step 3: Analyze Each Statement
1. **Statement 1**: "In the center of each I band is an elastic fiber called Z line which bisects this."
- This statement is correct. The Z line bisects the I band and serves as an attachment point for actin filaments.

2. **Statement 2**: "The thin filaments are firmly attached to the Z line."
- This statement is also correct. The actin filaments are indeed anchored to the Z line.

3. **Statement 3**: "M line is a fibrous membrane in the middle of A band."
- This statement is correct as well. The M line is located in the center of the A band and serves as an attachment point for myosin filaments.

### Step 4: Conclusion
Since all the statements provided are correct, there is no incorrect statement among the options given. Therefore, the answer to the question is that none of the statements are false.

### Final Answer
**None of the statements about striated muscle are incorrect.**

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