Krogh length

The Krogh Length, $$\lambda_K$$, is the distance to which nutrients diffuse between capillaries, based on cellular consumption of the nutrients.

It can be described as:

$$\lambda_K = \sqrt{D_s c_o/R}$$

where $$D_s$$ is the diffusion constant of the solute in the substrate, $$c_o$$ is the concentration in the channel, and $$R$$ is the consumption by the cells. Units are in terms of length.