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Why do arteries have thick, elastic walls?

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Silhouette diagram of the human body highlighting the heart and major blood vessels, with labeled arteries in red and veins in blue to show the structure of the cardiovascular system. — Circulatory system Human circulatory system.

Arteries have thick, elastic walls primarily because they must transport blood under high pressure generated by the pumping action of the heart.12

The structural composition of these walls—which include smooth muscle cells and elastic fibres—allows arteries to withstand this force. Specifically, the elastic walls stretch and recoil with each heartbeat. This expansion and contraction, which creates the pulse, helps maintain continuous blood flow and stable blood pressure throughout the circulatory system as blood is forced into the arterial network.134

In contrast, veins have thinner, less elastic walls because the blood within them is under substantially lower pressure.5