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Possible functional consequences of structural adaptation along single arterioles
Author(s) -
Jacobsen Jens Christian Brings,
Hornbech Morten,
Henriksen Freja,
Jensen Lars Jørn,
HolsteinRathlou NielsHenrik
Publication year - 2009
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.23.1_supplement.949.11
Subject(s) - tapering , radius , mechanics , materials science , anatomy , physics , biology , computer graphics (images) , computer security , computer science
Arterioles are normally thought of as having a constant structural diameter between branch points. In unbranched rat cremaster arterioles, however, structural diameter increases downstream along the vessel (upstream tapering) without change in cross‐sectional area of the vascular wall (1). We addressed the possible functional consequence of this configuration by flow‐simulations comparing myogenically active vessels of uniform structural radius with those having an upstream tapering shape. In our model cross‐sectional area of the vascular wall remains invariant along the vessel and the flow is the same in all cases. Results The vascular wall material can be arranged in an upstream tapering configuration such that circumferential wall stress is uniform along the vessel. The stress remains uniform during flow‐autoregulation when perfusion pressure is changed. In contrast, when the structural radius is uniform along the vessel wall stress is much higher upstream than downstream, and this difference is maintained under variations in perfusion pressure. Conclusion In a myogenically active vessel upstream tapering of the inner radius allows the circumferential wall stress, and hence possibly the contractile state of the wall smooth muscle cells, to remain constant along the vessel at a given pressure. This is not the case for a vessel with a uniform radius. The upstream tapering shape is consistent with the vascular wall cells having a uniform point of operation as regards stress‐induced myogenic contraction.