What is the characteristic feature of arteries compared to veins?

Arteries are characterized by having thick walls primarily due to the need to withstand and regulate the high pressure at which blood is pumped from the heart. The muscular layer in the walls of arteries allows them to constrict and dilate, helping to maintain blood pressure and flow. This thick structure is essential for their role in transporting oxygenated blood (with the exception of the pulmonary arteries) from the heart to various tissues throughout the body.

In contrast, veins have thinner walls and are designed to carry blood back to the heart under lower pressure. They also contain valves that prevent the backflow of blood, ensuring it moves in a single direction, which is particularly important in the extremities where blood must travel against gravity. While both types of blood vessels play vital roles in circulation, the structural differences, particularly the thickness of their walls, are a fundamental characteristic that distinguishes arteries from veins.