C	oxygen-binding capacity of blood
D	oxygen diffusion coefficient
H	thickness of the tissue
Ht	tube hematocrit
J	capillary-tissue diffusive flux
L	length of the capillary
l	penetration depth
M	oxygen consumption rate per unit volume of tissue
P	oxygen tension
r	capillary radius
R	Krogh cylinder radius
υ	velocity of blood
υpl	mean velocity of plasma
υc	mean velocity of red blood cells
x, y, z	dimensional coordinates
x*, y*, z*	dimensionless coordinates
GREEK SYMBOLS
α	oxygen solubility coefficient
ψ	oxygen saturation fraction of hemoglobin
SUBSCRIPTS
a	pertaining to arterial end of the capillaries
b	pertaining to blood
Hb	pertaining to hemoglobin solution
i = 1, 2, 3, 4	pertaining to capillaries
K	pertaining to “Krogh-like” geometry
pl	pertaining to plasma
s	pertaining to the surface of the tissue