Oxygen transport to tissue and the Krogh-Erlang model

2 Oxygen transport to tissue and the Krogh-Erlang model 

Spatially distributed systems and reaction-diffusion modeling 

664 x 10-4 M sec-1. Given values of c0, D, and M, the maximal width of the slab that maintains positive oxygenation is computed Lmax = (2I)c /M)l/ . At D = 2 x 10-5 cm2 sec-1, M = 2x 10-4 M sec-1, and c0 = 2.6 x 10-5 M, the maximal diffusion distance is Lmax 22.8 pm. This value provides an approximation of the maximal distance over which diffusion can effectively supply oxygen to tissue at this rate of oxygen consumption. Clearly this length is much shorter than the typical dimensions of most multicellular organisms. Certainly the distance between most cells in the human body and the atmosphere is much greater than 23 pm. 

3 In the early 1600s William Harvey deduced the existence of the microcirculation. Until then it was thought that venous blood and arterial blood made up independent pools. Capillary vessels were first observed later in die century by Marcello Malpighi, verifying the existence of a microcirculation connecting die arterial and venous networks. 

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