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https://hdl.handle.net/2440/134506
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Type: | Journal article |
Title: | Relationship between capillaries, mitochondria and maximum power of the heart: a meta-study from shrew to elephant |
Author: | Horrell, H.D. Lindeque, A. Farrell, A.P. Seymour, R.S. White, C.R. Kruger, K.M. Snelling, E.P. |
Citation: | Proceedings of the Royal Society B: Biological Sciences, 2022; 289(1968):20212461-20212461 |
Publisher: | The Royal Society |
Issue Date: | 2022 |
ISSN: | 0962-8452 1471-2954 |
Statement of Responsibility: | Heidi D. Horrell, Anika Lindeque, Anthony P. Farrell, Roger S. Seymour, Craig R. White, Kayla M. Kruger and Edward P. Snelling |
Abstract: | This meta-study uses phylogenetic scaling models across more than 30 species, spanning five orders of magnitude in body mass, to show that cardiac capillary numerical density and mitochondrial volume density decrease with body mass raised to the -0.07 ± 0.03 and -0.04 ± 0.01 exponents, respectively. Thus, while an average 10 g mammal has a cardiac capillary density of approximately 4150 mm<sup>-2</sup> and a mitochondrial density of 33%, a 1 t mammal has considerably lower corresponding values of 1850 mm<sup>-2</sup> and 21%. These similar scaling trajectories suggest quantitative matching for the primary oxygen supply and oxygen consuming structures of the heart, supporting economic design at the cellular level of the oxygen cascade in this aerobic organ. These scaling trajectories are nonetheless somewhat shallower than the exponent of -0.11 calculated for the maximum external mechanical power of the cardiac tissue, under conditions of heavy exercise, when oxygen flow between capillaries and mitochondria is probably fully exploited. This mismatch, if substantiated, implies a declining external mechanical efficiency of the heart with increasing body mass, whereby larger individuals put more energy in but get less energy out, a scenario with implications for cardiovascular design, aerobic capacity and limits of body size. |
Keywords: | body size capillaries heart mitochondria power scaling |
Rights: | © 2022 The Author(s) Published by the Royal Society. All rights reserved. |
DOI: | 10.1098/rspb.2021.2461 |
Grant ID: | http://purl.org/au-research/grants/arc/DP170104952 |
Published version: | http://dx.doi.org/10.1098/rspb.2021.2461 |
Appears in Collections: | Environment Institute publications |
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