Premium
Microvascular network structure minimizes energy dissipation and maximizes pulse transmission
Author(s) -
Shaw Dana K,
Coverley Catherine R,
Hakun Emily,
Jennings Bryon,
Quick Christopher M,
Mohiuddin Mohammad W
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a484-d
Subject(s) - hemodynamics , dissipation , bifurcation , pulse (music) , shear stress , mechanics , anatomy , physics , nonlinear system , optics , cardiology , biology , medicine , thermodynamics , quantum mechanics , detector
Two principles have been proposed to govern the branching pattern of arterial conductance vessels. Whereas Murray proposed that the arterial system minimizes energy dissipation, Karreman proposed that the arterial system minimizes pulse wave reflection. Arterial branches exhibit topologies and hemodynamics predicted by both principles. We hypothesized that these two principles also explain topologies and hemodynamics of arteriolar networks. We tested this hypothesis theoretically by showing that both principles can be true at the same time, mathematically predicting network asymmetry and nonlinear pressure‐radii relationships. We tested this hypothesis experimentally by noninvasively recording the radii (20–90 ìm) and blood flow velocities at arteriolar branches in the wings of Pallid bats. Unanaesthetized bats (n=10) were placed inside a pressurized restraint box with the wing spread under a microscope. Consistent with both principles, endothelial shear stress deviated little from one generation to the next, and pulses were transmitted even to the smallest arterioles. Under normal pressures, the mother vessel radii for each bifurcation deviated 5.7±4.2% from the Murray optimum and 5.8±4.3% from the Karreman optimum. Deviations were 5.1±3.2% and 4.6±3.5%, respectively, when arterial pressure was raised by 10–35mmHg, suggesting both principles are essential for hemodynamic homeostasis.