Veins and Arteries in Microscopy: Both Appear Rounded

Contrary to common misconception, both veins and arteries appear cylindrical and rounded in cross-sectional micrographs when cut perpendicular to their long axis. The distinction lies in wall thickness, lumen size, and histological features — not overall shape.

Arteries have thicker muscular walls and smaller lumens; veins have thinner walls, larger lumens, and often contain valves. Both are tubular structures that appear circular in transverse section.