Which statement correctly contrasts elastic arteries and muscular arteries in structure and function?

• A. Elastic arteries contain many elastic fibers in the media to absorb pressure, while muscular arteries have more smooth muscle in the media to regulate distribution; both are part of the systemic arterial tree.
• B. Elastic arteries have less smooth muscle in the media than muscular arteries; both function only in large vessel substitution.
• C. Muscular arteries rely on elastic fibers to absorb pressure; elastic arteries regulate distribution with smooth muscle.
• D. Both types lack smooth muscle and rely on connective tissue for tone.

Answer: (A)

Understanding how the tunica media differs between elastic and muscular arteries helps explain their distinct roles in circulation. Elastic arteries have a media packed with elastic fibers plus relatively less smooth muscle. That elastic-rich wall can stretch when the heart ejects blood and then recoil, which dampens the surge of pressure and helps maintain steady blood flow between heartbeats. This makes them ideal as conductors that handle the high-volume, pulsatile output from the heart.

Muscular arteries, by contrast, have a thicker media dominated by smooth muscle and fewer elastic fibers. The abundance of smooth muscle enables active constriction and dilation, allowing precise control of blood flow to specific organs and tissues and helping regulate overall systemic vascular resistance. They’re the key distributors, routing blood where it’s needed and adjusting flow as demands change.

Both types are part of the systemic arterial tree, but they specialize differently: elastic arteries dampen pressure fluctuations to smooth out flow, while muscular arteries actively regulate distribution through vasomotion. The statement that matches this distinction captures the structural emphasis on elastic fibers for damping in elastic arteries and smooth muscle for distribution in muscular arteries.