| Calculated dispersion of capillary transit times: significance for oxygen exchange. | |
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MedLine Citation:
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PMID: 7468815 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Probability densities for red cell velocity (V) and capillary length (L) in dog gracilis muscles were computed from mean length and mean velocity assuming two-parameter gamma distributions [Honig, Feldstein, and Frierson, Am. J. Physiol. 233 (Heart Circ. Physiol. 2): H122-H129, 1977]. The distribution of capillary transit times (L/V) was obtained from the ratio of the two gamma distributions. The lower tails of transit time distributions were compared with times thought required for O2 release from capillaries. Results indicate the following. 1) Transit time exceeds O2 release time at rest in all capillaries, regardless of assumptions in the calculation. 2) Transit time appears long enough even in moderate exercise provided mean L is about 1,000 microns and release time is about 100 ms. 3) Capillary recruitment prevents a functional O2 shunt during work at one- to two-thirds maximum O2 uptake (VO2max). 4) Recruitment is insufficient to prevent O2 shunting during exercise to VO2max. 5) Quantitative analysis of O2 transport is severely limited by lack of information about a) microvascular geometry, b) the probability distributions of parameters, and c) the kinetics of O2 release from capillaries. |
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Authors:
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C R Honig; C L Odoroff |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 240 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1981 Feb |
Date Detail:
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Created Date: 1981-04-24 Completed Date: 1981-04-24 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: H199-208 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Capillaries / physiology* Cell Movement Dogs Erythrocytes / physiology* Mathematics Models, Biological* Muscles / blood supply* Oxygen Consumption* Physical Exertion |
| Grant Support | |
ID/Acronym/Agency:
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HLB-03290/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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