Which one is not supplied exclusively with involuntary muscles ?

Options

A. Iris
B. Gland ducts
C. Urethra
D. Coats of blood vessel

Answer

To solve the question "Which one is not supplied exclusively with involuntary muscles?", we can analyze each option provided.

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify which of the given options is not solely controlled by involuntary muscles. Involuntary muscles are those that are not under conscious control, such as smooth muscles found in various organs.

2. **Analyze the Options**:
- **Iris**: The iris of the eye is controlled by involuntary muscles. These muscles adjust the size of the pupil in response to light. Therefore, this option is incorrect.

- **Gland Ducts**: Gland ducts also contain smooth muscles that are involuntary. These muscles help in the movement of secretions from glands. Thus, this option is also incorrect.

- **Coats of Blood Vessels**: Blood vessels have a layer of smooth muscle (involuntary) that helps regulate blood flow and pressure. Hence, this option is incorrect as well.

- **Urethra**: The urethra has two types of sphincters. One is a voluntary sphincter (external sphincter) that we can control consciously, while the other is involuntary (internal sphincter). This means that the urethra is not exclusively supplied with involuntary muscles.

3. **Conclusion**: Based on the analysis, the correct answer is the **urethra**, as it contains both voluntary and involuntary muscles.

### Final Answer:
The urethra is not supplied exclusively with involuntary muscles.

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