Dihedral angles of septal "bend" structures in lung
parenchyma.
Butler, J. P., E. H. Oldmixon, and F. G. Hoppin, Jr.
Physiology Program, Harvard School of Public Health, Boston, MA,
and Department of Medicine, Memorial Hospital of Rhode Island and
Brown University, Providence, RI
APStracts 3:0247A, 1996.
Alveolar parenchyma comprises two interacting tensile systems: the
cable system (a network of linear condensations of connective tissue)
and the membrane system (a network of quasi-planar alveolar septa).
Inferences can be drawn about the mechanics of this structure from
its configuration. We reported earlier that the angles between
alveolar septa, at the common 3-way junctions (J), are nearly
uniform, indicating that septal tensions are also nearly uniform. We
now report on the interseptal angles at the next most common class of
septal junction ("B"), a structure where two septa meet along
a segment of the cable system. We find, first, that the distributions
of interseptal angles at B junctions have means above 120o, are
narrow, and have few, if any, angles below 120o. The findings of
uniform 120o angles at J junctions and a cut-off below 120o at B
junctions are also characteristic of soap films supported on a frame,
which follows the physical principle of surface area minimization. We
suggest that this principle may be operative in parenchymal
development and remodeling.
Received 16 August 1995; accepted in final form 9 May 1996.
APS Manuscript Number A901-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 June 96