Which has non muscular walls

Options

A. capillary
B. arteriole
C. veins
D. artery

Answer

To determine which structure has non-muscular walls, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding the Question:**
The question asks which of the given options has non-muscular walls. We need to evaluate each option to identify the correct answer.

2. **Analyzing the First Option: Capillary**
- Capillaries are the smallest blood vessels in the body.
- They have walls that are only one cell thick, made up of squamous epithelial cells.
- Since they lack muscular walls, this option is correct.

3. **Analyzing the Second Option: Arteriole**
- Arterioles are small blood vessels that branch from arteries.
- They have muscular walls that help regulate blood flow and pressure.
- Therefore, this option is incorrect.

4. **Analyzing the Third Option: Vein**
- Veins are blood vessels that carry blood back to the heart.
- They have muscular walls, although they are thinner than those of arteries.
- Thus, this option is also incorrect.

5. **Analyzing the Fourth Option: Artery**
- Arteries are blood vessels that carry oxygenated blood away from the heart.
- They have thick muscular walls to withstand high pressure.
- Therefore, this option is incorrect as well.

6. **Conclusion:**
- The only structure with non-muscular walls is the capillary.
- Thus, the correct answer is **Capillary**.

### Final Answer:
**Capillary has non-muscular walls.**