The zero-stress state of rat veins and vena cava

J. P. Xie, S. Q. Liu, R. F. Yang, Y. C. Fung

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62 Scopus citations

Abstract

The zero-stress state ofa vein is, like that ofan artery, not a closed cylindrical tube, but is a series ofsegments whose cross-sections are open sectors. An opening angle ofeach sector is defined as the angle subtended between two radiijoining the midpoint of the inner wall to the tips of the inner wall. Data on the opening angles (mean ± standard deviation) of the veins and vena cava of the rat are presented. For the superior vena cava and subclavian, jugular, facial, renal, common iliac, saphenous, and plantar veins, the opening angle varies in the range of25 to 75 deg. The inferior vena cava (below the heart), however, has noncircular, nonaxisymmetric cross-sections, a curved axis, and a rapid longitudinal variation of its "diameter"; its zero-stress state is not circular sectors; but the opening angle is still a useful characterization. The mean opening angle of the interior vena cava varies in the range of40 to 150 deg in the thoracic portion, and 75 to 130 deg in the abdominal portion, with the larger values occurring about the middle of each portion. There are considerable length, diameter reductions, and wall thickening of the vena cava from the homeostatic state to the no-load state in vitro. Physically, the zero-stress state is the basis of the stress analysis of blood vessels. The change of opening angle is a convenient parameter to characterize any nonuniform remodeling of the vessel wall due to changes in physical stress or chemical environment. Change of zerostress state influences the compliance and collapsibility of the viens, their pressurevolume and pressure-flow relationships, the waterfall phenomenon, and the tone in the vascular smooth muscles if the homeostatic stress is changed.

Original languageEnglish (US)
Pages (from-to)36-41
Number of pages6
JournalJournal of Biomechanical Engineering
Volume113
Issue number1
DOIs
StatePublished - Feb 1991

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physiology (medical)

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