Surface Effects

Flow patterns looping in and around conformations in a surface are complex. Uptake and discharge mechanisms involve transport across surfaces interfacing between two media.

Might we infer from considering the surfaces of the hemo-coel what events might transpire on or near them as molecules of nutrients, wastes and hormones traverse the boundaries outward from cells to hemolymph and inward from hemolymph into cells?

Analogous surfaces include digestive and respiratory surfaces. We know from studies at the microscale level of resolution that respiratory membranes and intestinal surfaces are complex and irregular. Both have in common extended surface areas that enhance trans-surface transport dynamics. Such extended surfaces are often folded, packed or rolled up conserving space. We minimize the volume subsumed by a surface if we fold, crumple or compress larger surfaces. Even if such surfaces behave within limits as ergodic fractals, randomness presents similar patterns to surfaces existing across different scales.

Over the course of a lifetime, surface structures may evolve through developmental sequences passing through an array of forms and functions. We can estimate fractal dimension from the slope of a log-log regression curve, but to do so we must discard much structural information. For example, as we have seen, insects have solved distribution problems uniquely by coupling a direct point-to-point distribution system with a more general one. The tubular system of tracheae and tracheoles supplies gaseous oxygen diffusing through air directly from the spiracles to metabolizing muscle while simultaneously, foodstuffs and wastes distribute generally to these same tissues through the circulating hemolymph.

What happens when hemolymph encounters surfaces and contours as it percolates from the aorta back through the cavity of the hemocoel? By extension, how might technology duplicate what happens in the hemocoel-hemolymph system in microflu-idic chips or other systems composed of materials such as porous polymers?

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