In arteries, which tunic is the most prominent?

• A. Tunica media
• B. Tunica adventitia
• C. Tunica intima
• D. None of the above

Answer: (A)

The middle layer does the heavy lifting in arteries. The tunica media is the thick, muscular layer made mostly of smooth muscle arranged in circles around the vessel, with elastic fibers in elastic arteries to help with recoil. This prominent muscular layer gives arteries their strength and lets them constrict or dilate to regulate blood flow and pressure. By contrast, the tunica intima is a thin endothelial lining on the inside, and the tunica adventitia is the outer connective tissue layer that is usually thinner than the media in most arteries. So, the tunica media stands out as the most prominent tunic in arterial walls because it provides both structural support and the ability to adjust vessel diameter.