As compared to artery, a vein has

Options

A. (l)thinner walls
B. (2)larger lumen
C. (3) less musculature.
D. (4) all of the above

Answer

### Step-by-Step Solution:

1. **Understanding the Function of Arteries and Veins**:
- Arteries are responsible for carrying oxygenated blood away from the heart to various parts of the body.
- Veins carry deoxygenated blood from the body back to the heart.

2. **Comparing the Structure of Arteries and Veins**:
- **Wall Thickness**:
- Arteries have thick muscular walls to withstand high pressure from the blood pumped by the heart.
- Veins have thinner walls compared to arteries, as the blood in veins is under lower pressure.
- **Lumen Size**:
- The lumen (the interior space of the blood vessel) of arteries is narrow to maintain high pressure.
- The lumen of veins is larger, allowing them to accommodate a larger volume of blood at lower pressure.
- **Presence of Valves**:
- Arteries do not have valves because the high pressure keeps the blood flowing in one direction.
- Veins have valves to prevent backflow of blood, ensuring it moves toward the heart.

3. **Blood Flow Characteristics**:
- Blood flow in arteries is pulsatile and under high pressure, leading to jerky movements.
- Blood flow in veins is smoother and under lower pressure, without jerky movements.

4. **Conclusion**:
- Based on the comparisons, veins have:
- Thinner walls than arteries.
- Larger lumen than arteries.
- Less muscular structure than arteries.
- Therefore, the correct answer is that veins have thinner walls, larger lumen, and are less muscular compared to arteries.

### Final Answer:
Veins have thinner walls, larger lumen, and are less muscular compared to arteries.