Why do arteries have thick and elastic walls whereas veins have valves?
Answer:
Arteries are the blood vessels which carry oxygenated blood away from the heart to all the body parts. So, the pressure of blood is more in arteries as compared to the veins which carry deoxygenated blood from body parts back to the heart. In order to avoid the rupture of arteries due to high blood pressure, they have comparatively thick elastic walls.
Veins have valves in order to prevent the backflow of blood which ensures that the blood flows only in one direction.
