In skeletal muscle Z-line is connected to

Options

A. Actin
B. Myosin
C. Tropomyosin
D. Hensen's line.

Answer

### Step-by-Step Solution:

1. **Understanding the Z-line**: The Z-line is a structural component of the sarcomere, which is the basic contractile unit of skeletal muscle. It serves as the boundary between adjacent sarcomeres.

2. **Identifying Components of the Sarcomere**: Each sarcomere contains two types of filaments: thin filaments (actin) and thick filaments (myosin). The arrangement of these filaments gives muscle its striated appearance.

3. **Connection of Actin to the Z-line**: The Z-line is specifically connected to the thin filaments, which are primarily composed of actin. Actin filaments extend from the Z-line towards the center of the sarcomere, overlapping with myosin filaments in the A-band region.

4. **Excluding Other Options**:
- **Myosin**: This is the thick filament and does not connect to the Z-line.
- **Tropomyosin**: This is a regulatory protein that wraps around actin filaments but does not connect directly to the Z-line.
- **Hansen's line**: This is a feature of the A-band and does not connect to the Z-line.

5. **Conclusion**: Therefore, the Z-line is connected to actin filaments, making "actin" the correct answer.

### Final Answer:
The Z-line in skeletal muscle is connected to **actin**.

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