Why are the walls of arteries relatively thicker than those corresponding veins?

Arteries have relatively thicker walls compared to veins for several reasons:

* Higher Pressure: Arteries carry oxygenated blood away from the heart, and this blood is under higher pressure than the blood in veins. The walls of arteries need to be strong enough to withstand this higher pressure without rupturing.

* Tunica Media: Arteries have a thicker layer of smooth muscle in their walls, known as the tunica media. This layer of muscle is responsible for regulating blood flow by constricting or dilating the artery. Veins have a thinner layer of smooth muscle and rely more on valves to control blood flow.

* Structural Differences: The walls of arteries contain more elastic fibers and collagen than veins. These proteins provide strength and elasticity to the arterial walls, allowing them to withstand pressure and recoil after stretching.

* Oxygen Transport: The thicker walls of arteries also help to maintain the pressure necessary for the efficient transport of oxygenated blood to body tissues.