Table 4 Parameters and units of the brain capillary system. The physiological range of values of the parameters is given for rat and human, based on references from the literature

Capillary radius (10⁻⁶ m)

0.8–4.8 [4, 5, 7, 213]

3−5 [17, 214, 215]

S, capillary surface area (m²)

1.3 [216]

15–25 [17, 113, 217]

Intercapillary distance (10⁻⁶ m)

14–72 [4, 5, 213]

40 [17, 129, 218]–60 [214]

Q, capillary blood flow rate (10⁻⁹ L min⁻¹)

4.82–8.83 [219]

0.3–200 [114]

V_brain, brain volume (g)

1.8 [171, 220]

1400 [41]

Capillary blood flow velocity (10⁻⁴ m s⁻¹)

0.5−50 [221,222,223,224,225,226]

–