Document Detail


The right-to-left shunt of crocodilians serves digestion.
MedLine Citation:
PMID:  18194087     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Abstract All amniotes except birds and mammals have the ability to shunt blood past the lungs, but the physiological function of this ability is poorly understood. We studied the role of the shunt in digestion in juvenile American alligators in the following ways. First, we characterized the shunt in fasting and postprandial animals and found that blood was shunted past the lungs during digestion. Second, we disabled the shunt by surgically sealing the left aortic orifice in one group of animals, and we performed a sham surgery in another. We then compared postprandial rates of gastric acid secretion at body temperatures of 19 degrees and 27 degrees C and rates of digestion of bone at 27 degrees C. Twelve hours after eating, maximal rates of gastric acid secretion when measured at 19 degrees and 27 degrees C were significantly less in the disabled group than in sham-operated animals. Twenty-four hours postprandial, a significant decrease was found at 27 degrees C but not at 19 degrees C. For the first half of digestion, dissolution of cortical bone was significantly slower in the disabled animals. These data suggest the right-to-left shunt serves to retain carbon dioxide in the body so that it can be used by the gastrointestinal system. We hypothesize that the foramen of Panizza functions to enrich with oxygen blood that is destined for the gastrointestinal system to power proton pumps and other energy-demanding processes of digestion and that the right-to-left shunt serves to provide carbon dioxide to gastrointestinal organs besides the stomach, such as the pancreas, spleen, upper small intestine, and liver.
Authors:
C G Farmer; T J Uriona; D B Olsen; M Steenblik; K Sanders
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  81     ISSN:  1522-2152     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2008 Mar-Apr
Date Detail:
Created Date:  2008-02-06     Completed Date:  2008-04-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  125-37     Citation Subset:  IM    
Affiliation:
Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA. farmer@biology.utah.edu
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MeSH Terms
Descriptor/Qualifier:
Alligators and Crocodiles / physiology*
Animals
Aorta / physiology
Blood Circulation / physiology*
Blood Flow Velocity / physiology
Digestion / physiology*
Energy Metabolism
Heart / physiology
Postprandial Period

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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