Hensen's disc occurs in

Options

A. Myofibril of striated muscle
B. Myofibril of unstriated muscle
C. Myofibril of heart muscle
D. None of the above.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks where Hensen's disc occurs. We need to identify the type of muscle that contains Hensen's disc.

2. **Types of Muscles**: There are three main types of muscles in the human body:
- Striated muscles (skeletal muscles)
- Unstriated muscles (smooth muscles)
- Cardiac muscles (heart muscles)

3. **Characteristics of Striated Muscles**: Striated muscles have a distinct structure where myofibrils are arranged into units called sarcomeres. These sarcomeres exhibit alternating light and dark bands due to the presence of thick (myosin) and thin (actin) filaments.

4. **Identifying Hensen's Disc**: Within the sarcomere, there is a specific region known as the H zone or Hensen's disc. This region is characterized by the absence of actin filaments and consists solely of myosin filaments.

5. **Evaluating the Options**:
- **Option 1**: Myofibrils of striated muscles - This is correct as Hensen's disc is found in the H zone of striated muscle sarcomeres.
- **Option 2**: Myofibrils of unstriated muscles - Incorrect, as unstriated muscles do not have the same banding pattern.
- **Option 3**: Myofibrils of heart muscles - Incorrect, as cardiac muscles have a different structure and do not specifically refer to Hensen's disc.
- **Option 4**: None of the above - Incorrect, since option 1 is correct.

6. **Conclusion**: The correct answer is that Hensen's disc occurs in the myofibrils of striated muscles.

**Final Answer**: Hensen's disc occurs in the myofibrils of striated muscles.

---