Document Detail

Quantitative assessments of morphological and functional properties of biological trees based on their fractal nature.
MedLine Citation:
PMID:  17347385     Owner:  NLM     Status:  MEDLINE    
The branching systems in our body (vascular and bronchial trees) and those in the environment (plant trees and river systems) are characterized by a fractal nature: the self-similarity in the bifurcation pattern. They increase their branch density toward terminals according to a power function with the exponent called fractal dimension (D). From a stochastic model based-on this feature, we formulated the fractal-based integrals to calculate such morphological parameters as aggregated branch length, surface area, and content volume for any given range of radius (r). It was followed by the derivation of branch number and cross-sectional area, by virtue of the logarithmic sectioning of the r axis and of the branch radius-length relation also given by a power function of r with an exponent (alpha). These derivatives allowed us to quantify various hydrodynamic parameters of vascular and bronchial trees as fluid conduit systems, including the individual branch flow rate, mean flow velocity, wall shear rate and stress, internal pressure, and circumferential tension. The validity of these expressions was verified by comparing the outcomes with actual data measured in vivo in the vascular beds. From additional analyses of the terminal branch number, we found a simple equation relating the exponent (m) of the empirical power law (Murray's so-called cube law) to the other exponents as (m=D+alpha). Finally, allometric studies of mammalian vascular trees revealed uniform and scale-independent distributions of terminal arterioles in organs, which afforded an infarct index, reflecting the severity of tissue damage following arterial infarction.
Akira Kamiya; Tatsuhisa Takahashi
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Publication Detail:
Type:  Journal Article     Date:  2007-03-08
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  102     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-06-06     Completed Date:  2007-11-05     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2315-23     Citation Subset:  IM    
Nihon University General Research Center, Tokyo, Japan.
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MeSH Terms
Blood Vessels / anatomy & histology*,  growth & development*
Bronchi / anatomy & histology*,  growth & development*
Computer Simulation
Models, Anatomic
Models, Biological*
Models, Statistical
Morphogenesis / physiology*
Stochastic Processes

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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