Choose the INCORRECT statement in reference to the unstriated muscles.

Options

A. Their contractions are under the control of autonomous nervous system
B. Cell junction hold them together
C. They lack actin and myosin proteins , hence lack striations
D. They possess uninucleated , fusiform -shaped cells which taper at both the ends

Answer

To solve the question regarding the incorrect statement about unstriated muscles, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Unstriated Muscles**: Unstriated muscles, also known as smooth muscles, are involuntary muscles that do not have striations (light and dark bands) when viewed under a microscope.

2. **Analyze Each Statement**:
- **Statement 1**: "Their contractions are under the control of the autonomic nervous system."
- This statement is **correct**. Unstriated muscles are indeed controlled by the autonomic nervous system.

- **Statement 2**: "Cell junctions hold them together."
- This statement is also **correct**. Smooth muscle cells are connected by cell junctions, which help in coordinating contractions.

- **Statement 3**: "They lack myosin and actin protein, hence lack stress."
- This statement is **incorrect**. Unstriated muscles do contain myosin and actin proteins, which are essential for muscle contraction. The presence of these proteins is what allows them to generate force (stress).

- **Statement 4**: "They possess uninucleated, visiform-shaped cells which taper at the ends."
- This statement is **correct**. Smooth muscle cells are typically uninucleated and have a spindle or fusiform shape, tapering at both ends.

3. **Identify the Incorrect Statement**: Based on the analysis, the third statement is the only incorrect statement regarding unstriated muscles.

### Conclusion:
The incorrect statement in reference to unstriated muscles is: **"They lack myosin and actin protein, hence lack stress."**

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