Document Detail

Intrinsic pump-conduit behavior of lymphangions.
MedLine Citation:
PMID:  17122333     Owner:  NLM     Status:  MEDLINE    
Lymphangions, segments of lymphatic vessels bounded by valves, have characteristics of both ventricles and arteries. They can act primarily like pumps when actively transporting lymph against a pressure gradient. They also can act as conduit vessels when passively transporting lymph down a pressure gradient. This duality has implications for clinical treatment of several types of edema, since the strategy to optimize lymph flow may depend on whether it is most beneficial for lymphangions to act as pumps or conduits. To address this duality, we employed a simple computational model of a contracting lymphangion, predicted the flows at both positive and negative axial pressure gradients, and validated the results with in vitro experiments on bovine mesenteric vessels. This model illustrates that contraction increases flow for normal axial pressure gradients. With edema, limb elevation, or external compression, however, the pressure gradient might reverse, and lymph may flow passively down a pressure gradient. In such cases, the valves may be forced open during the entire contraction cycle. The vessel thus acts as a conduit, and contraction has the effect of increasing resistance to passive flow, thus inhibiting flow rather than promoting it. This analysis may explain a possible physiological benefit of the observed flow-mediated inhibition of the lymphatic pump at high flow rates.
Christopher M Quick; Arun M Venugopal; Anatoliy A Gashev; David C Zawieja; Randolph H Stewart
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-11-22
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  292     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2007 Apr 
Date Detail:
Created Date:  2007-04-04     Completed Date:  2007-05-23     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1510-8     Citation Subset:  IM    
College of Veterinary Medicine, 4466 Texas A and M University, College Station, TX 77843-4466, USA.
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MeSH Terms
Computational Biology
Computer Simulation
Hydrogen-Ion Concentration
Lymph / physiology*
Lymphatic System / physiology*
Models, Theoretical
Muscle Contraction
Muscle, Smooth / physiology
Grant Support
Reg. No./Substance:

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