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Mechanism of the rigidity of pulmonary capillaries in avian lung
Author(s) -
Watson Rebecca R.,
Fu Zhenxing,
West John B
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1150.13
Subject(s) - rigidity (electromagnetism) , capillary action , chemistry , extracellular matrix , anatomy , capillary pressure , lung , biophysics , mechanics , materials science , composite material , biology , physics , medicine , biochemistry , porous medium , porosity
We have previously shown that the pulmonary capillaries in chicken lungs are extraordinarily rigid in that large alterations in the capillary transmural pressure result in only small changes in capillary diameter. For example, the capillaries remain wide open even when the pressure outside them is raised 35 cmH2O above the pressure inside them. Since the walls of the capillaries are exceedingly thin (mean thickness ca. 0.27 μ m) it seems unlikely that the rigidity can be explained by the walls themselves. However the capillary walls are tethered by epithelial bridges that form the walls of the surrounding air capillaries and these could provide the necessary support. The bridges themselves are composed of two epithelial sheets enclosing a small amount of tissue, presumably extracellular matrix, and their total thickness is as little as 0.1 μ m in some places. Therefore at first sight they do not seem strong enough to offer sufficient support. However because of the topographical arrangement of the bridges it is possible that the mechanical loads are shared in such a way that even these thin structures can provide the necessary support just as the thin spokes of a bicycle wheel confer remarkable rigidity to the wheel. Supported by NIH grants 5 RO1 HL60968 and 5 T32 HL07212.