Vessel Cross-Sectional Area (cm2) Aorta 2.5 Small arteries 20 Arterioles 40 Capillaries 2500 Venules 250 Small veins 80
Venae cavae 8
Note particularly the much larger cross-sectional areas of the veins than of the
arteries, averaging about four times those of the corresponding arteries. This explains the large blood
storage capacity of the venous system in comparison with the arterial system. Because the same
volume of blood flow (F) must pass through each segment of the circulation each minute, the velocity
of blood flow (v) is inversely proportional to vascular cross-sectional area (A):
