Abstract：
:Lymph is transported along collecting lymphatic vessels by intrinsic and extrinsic pumping. The walls have muscle of a type intermediate between blood-vascular smooth muscle and myocardium; a contracting segment between two valves (a lymphangion) constitutes a pump. This intrinsic mechanism is investigated ex vivo in isolated, spontaneously contracting, perfused segments subjected to controlled external pressures. The reaction to varying afterload is probed by slowly ramping up the outlet pressure until pumping fails. Often the failure occurs when the contraction raises intra-lymphangion pressure insufficiently to overcome the outlet pressure, open the outlet valve and cause ejection, but many segments fail by other means, the mechanisms of which are not clear. We here elucidate those mechanisms by resort to a numerical model. Experimental observations are paired with comparable findings from computer simulations, using a lumped-parameter model that incorporates previously measured valve properties, plus new measurements of active contractile and passive elastic properties, and the dependence of contraction frequency on transmural pressure, all taken from isobaric twitch contraction experiments in the same vessel. Surprisingly, the model predicts seven different possible modes of pump failure, each defined by a different sequence of valve events, with their occurrence depending on the parameter values and boundary conditions. Some, but not all, modes were found experimentally. Further model investigation reveals routes by which a vessel exhibiting one mode of failure might under altered circumstances exhibit another.
journal_name
Biomech Model Mechanobioljournal_title
Biomechanics and modeling in mechanobiologyauthors
Bertram CD,Macaskill C,Davis MJ,Moore JE Jrdoi
10.1007/s10237-017-0933-3subject
Has Abstractpub_date
2017-12-01 00:00:00pages
1987-2003issue
6eissn
1617-7959issn
1617-7940pii
10.1007/s10237-017-0933-3journal_volume
16pub_type
杂志文章abstract：:Flow-induced damage to red blood cells has been an issue of considerable importance since the introduction of the first cardiovascular devices. Early blood damage prediction models were based on measurements of damage by shear stress only. Subsequently, these models were extrapolated to include other components of the...
journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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journal_title：Biomechanics and modeling in mechanobiology
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