Table 2.

Anatomical power laws.

Parameter	Power law exponent	Tissue	Reference
N(r)	−2.7	pulmonary	Huang et al. (1996)
N(r)	−2.5	brain arterial	Mut et al. (2014)
N(r)	−1.3	cortex terminal arterial	Cassot et al. (2006)
N(r)	−3.0	Murray’s Law	Sherman (1981)
L(r)	+0.7	pulmonary	Huang et al. (1996)
L(r)	+1.3	cortex terminal arterial	Cassot et al. (2006)
L(r)	+0.75 to + 1.2	fractal tree structures	Hughes (2015) Takahashi (2014)

N(r) = number density, L(r) = vessel length as a function of r.