How do venous walls differ from those of the arteries?

The distinction in the structure of venous walls compared to arterial walls is primarily reflected in the thickness of the tunica media, which is the middle layer of the vessel wall.

In arteries, the tunica media is significantly thicker than in veins. This is primarily due to the functional demands placed on arteries, as they need to withstand higher pressure from the blood being pumped directly from the heart. The thicker tunica media in arteries contains more smooth muscle and elastic fibers, enabling them to regulate blood pressure and flow through vasoconstriction and vasodilation.

Venous walls, on the other hand, are designed to accommodate lower pressures and tend to be more compliant, which is why the tunica media is thinner. The primary function of veins is to return deoxygenated blood back to the heart, and while they do have some muscle and elastic tissue, it is not as pronounced as in arteries. This structural difference results in veins having larger lumens and being able to expand more easily, which facilitates blood return to the heart, especially through the use of one-way valves to prevent backflow.

The other options do not accurately reflect the structure of venous and arterial walls. Veins do not have more elastic tissue than arteries; they are typically less