Difference between artery and vein includes all, except

Options

A. Diameter of vessel
B. Valves
C. Elasticity of vessel wall, smooth muscles in tunica media
D. Type of cells in endothelium

Answer

To answer the question regarding the differences between arteries and veins, we need to analyze the characteristics of both types of blood vessels and identify which option does not represent a difference.

### Step-by-Step Solution:

1. **Understanding the Diameter of Vessels**:
- Arteries have a smaller diameter compared to veins. This is because arteries carry oxygenated blood under high pressure, while veins carry deoxygenated blood at lower pressure.
- **Conclusion**: The diameter of veins is larger than that of arteries.

2. **Presence of Valves**:
- Veins contain valves that prevent the backflow of blood, ensuring that it moves in one direction towards the heart.
- In contrast, arteries do not have valves because the high pressure of the blood flow keeps it moving forward.
- **Conclusion**: Valves are present in veins but absent in arteries.

3. **Elasticity of Vessel Walls**:
- The walls of arteries are more elastic than those of veins. This elasticity allows arteries to withstand and regulate the high pressure of blood pumped from the heart.
- Veins have thinner walls and less elasticity since they operate under lower pressure.
- **Conclusion**: Arteries have more elastic walls compared to veins.

4. **Type of Cells in Endothelium**:
- Both arteries and veins have endothelial cells lining their inner walls, but the structure of these cells can differ due to the varying functions and pressures in arteries and veins.
- The presence of elastic fibers is more prominent in arteries than in veins.
- **Conclusion**: There are differences in the types of cells and their arrangement in arteries and veins.

### Final Answer:
The difference between artery and vein includes all, except the presence of valves. Valves are present in veins but not in arteries.