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Estimating oxygen diffusive conductances of gas-exchange systems: A stereological approach illustrated with the human placenta.
MedLine Citation:
PMID:  23069190     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
For many organisms, respiratory gas exchange is a vital activity and different types of gas-exchange apparatus have evolved to meet individual needs. They include not only skin, gills, tracheal systems and lungs but also transient structures such as the chorioallantois of avian eggs and the placenta of eutherian mammals. The ability of these structures to allow passage of oxygen by passive diffusion can be expressed as a diffusive conductance (units: cm(3)O(2)min(-1)kPa(-1)). Occasionally, the ability to estimate diffusive conductance by physiological techniques is compromised by the difficulty of obtaining O(2) partial pressures on opposite sides of the tissue interface between the delivery medium (air, water, blood) and uptake medium (usually blood). An alternative strategy is to estimate a morphometric diffusive conductance by combining stereological estimates of key structural quantities (volumes, surface areas, membrane thicknesses) with complementary physicochemical data (O(2)-haemoglobin chemical reaction rates and Krogh's permeability coefficients). This approach has proved valuable in a variety of comparative studies on respiratory organs from diverse species. The underlying principles were formulated in pioneering studies on the pulmonary lung but are illustrated here by taking the human placenta as the gas exchanger.
Authors:
Terry M Mayhew
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-9-24
Journal Detail:
Title:  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft     Volume:  -     ISSN:  1618-0402     ISO Abbreviation:  Ann. Anat.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-10-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100963897     Medline TA:  Ann Anat     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier GmbH. All rights reserved.
Affiliation:
School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom. Electronic address: terry.mayhew@nottingham.ac.uk.
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