Z line or Krause membrane is present in the

Options

A. I band
B. A band
C. H band
D. Both (1) & (2)

Answer

To solve the question regarding the presence of the Z line or Krause membrane, we will analyze the options provided step by step.

### Step 1: Understand the Z line
The Z line, also known as the Krause membrane, is a structure found in striated muscle fibers. It serves as a boundary between adjacent sarcomeres, which are the basic contractile units of muscle tissue.

**Hint:** Recall that the Z line is crucial for muscle contraction and is found in specific types of muscle fibers.

### Step 2: Analyze the options
We have the following options:
1. I-band
2. A-band
3. H-band
4. Both 1 and 2

### Step 3: Identify where the Z line is located
- **I-band:** This is the region that contains only thin filaments (actin) and is bisected by the Z line. Therefore, the Z line is present in the I-band.

- **A-band:** This region contains both thick (myosin) and thin (actin) filaments. The Z line is not present in the A-band itself; rather, it is at the ends of the A-band.

- **H-band:** This is the central region of the A-band where there are only thick filaments. The Z line does not extend into the H-band.

- **Both 1 and 2:** Since the Z line is only present in the I-band and not in the A-band, this option is incorrect.

### Step 4: Conclusion
Based on the analysis, the Z line is present in the I-band only. Therefore, the correct answer to the question is option 1 (I-band).

**Final Answer:** The Z line or Krause membrane is present in the I-band.

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