HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (15) Citing Articles via Google Scholar Google Scholar Articles by Maina, J. N. Articles by West, J. B. Search for Related Content PubMed PubMed Citation Articles by Maina, J. N. Articles by West, J. B.

Thin and Strong! The Bioengineering Dilemma in the Structural and Functional Design of the Blood-Gas Barrier

School of Anatomical Sciences, Faculty of Health Sciences, The University of the Witwatersrand, Johannesburg, South Africa; and Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California

In gas exchangers, the tissue barrier, the partition that separates the respiratory media (water/air and hemolymph/blood), is exceptional for its remarkable thinness, striking strength, and vast surface area. These properties formed to meet conflicting roles: thinness was essential for efficient flux of oxygen by passive diffusion, and strength was crucial for maintaining structural integrity. What we have designated as "three-ply" or "laminated tripartite" architecture of the barrier appeared very early in the evolution of the vertebrate gas exchanger. The design is conspicuous in the water-blood barrier of the fish gills through the lungs of air-breathing vertebrates, where the plan first appeared in lungfishes (Dipnoi) some 400 million years ago. The similarity of the structural design of the barrier in respiratory organs of animals that remarkably differ phylogenetically, behaviorally, and ecologically shows that the construction has been highly conserved both vertically and horizontally, i.e., along and across the evolutionary continuum. It is conceivable that the blueprint may have been the only practical construction that could simultaneously grant satisfactory strength and promote gas exchange. In view of the very narrow allometric range of the thickness of the blood-gas barrier in the lungs of different-sized vertebrate groups, the measurement has seemingly been optimized. There is convincing, though indirect, evidence that the extracellular matrix and particularly the type IV collagen in the lamina densa of the basement membrane is the main stress-bearing component of the blood-gas barrier. Under extreme conditions of operation and in some disease states, the barrier fails with serious consequences. The lamina densa which in many parts of the blood-gas barrier is <50 nm thin is a lifeline in the true sense of the word.

This article has been cited by other articles:

				J. B. West Comparative physiology of the pulmonary blood-gas barrier: the unique avian solution Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2009; 297(6): R1625 - R1634. [Abstract] [Full Text] [PDF]

				M.-Y. Jian, J. A. King, A.-B. Al-Mehdi, W. Liedtke, and M. I. Townsley High Vascular Pressure-Induced Lung Injury Requires P450 Epoxygenase-Dependent Activation of TRPV4 Am. J. Respir. Cell Mol. Biol., April 1, 2008; 38(4): 386 - 392. [Abstract] [Full Text] [PDF]

				S. F. Perry and W. W. Burggren Why respiratory biology? The meaning and significance of respiration and its integrative study Integr. Comp. Biol., October 1, 2007; 47(4): 506 - 509. [Abstract] [Full Text] [PDF]

				S. Orgeig, W. Bernhard, S. C. Biswas, C. B. Daniels, S. B. Hall, S. K. Hetz, C. J. Lang, J. N. Maina, A. K. Panda, J. Perez-Gil, et al. The anatomy, physics, and physiology of gas exchange surfaces: is there a universal function for pulmonary surfactant in animal respiratory structures? Integr. Comp. Biol., October 1, 2007; 47(4): 610 - 627. [Abstract] [Full Text] [PDF]

				C. E. Perlman and J. Bhattacharya Alveolar expansion imaged by optical sectioning microscopy J Appl Physiol, September 1, 2007; 103(3): 1037 - 1044. [Abstract] [Full Text] [PDF]

				H. Zhou, N. Ohno, N. Terada, S. Saitoh, Y. Fujii, and S. Ohno Involvement of follicular basement membrane and vascular endothelium in blood follicle barrier formation of mice revealed by 'in vivo cryotechnique' Reproduction, August 1, 2007; 134(2): 307 - 317. [Abstract] [Full Text] [PDF]

				F. Blank, B. Rothen-Rutishauser, and P. Gehr Dendritic Cells and Macrophages Form a Transepithelial Network against Foreign Particulate Antigens Am. J. Respir. Cell Mol. Biol., June 1, 2007; 36(6): 669 - 677. [Abstract] [Full Text] [PDF]

				J. S. Torday and V. K. Rehan The evolutionary continuum from lung development to homeostasis and repair Am J Physiol Lung Cell Mol Physiol, March 1, 2007; 292(3): L608 - L611. [Abstract] [Full Text] [PDF]

				R. R. Watson, Z. Fu, and J. B. West Morphometry of the extremely thin pulmonary blood-gas barrier in the chicken lung Am J Physiol Lung Cell Mol Physiol, March 1, 2007; 292(3): L769 - L777. [Abstract] [Full Text] [PDF]