Date of Award
Doctor of Philosophy
Cardiac output and its distribution to specific tissues has been^measured in the intertidal abalone, Haliotis cracherodii (Mollusca,^Gastropoda). Thermodilution, a modification of the classical^indicator-dilution method, was used to measure cardiac output in^unanesthetized, unrestrained abalone under conditions of both^submergence and aerial exposure. Because of the nature of this^technique, the measurement could be completed within about 30^to 45 sec so that short term changes in cardiac output could be^monitored. Pulsatile aortic blood pressure was measured^simultaneously and allowed for the calculation of stroke volume. Insubmerged abalone a logarithmic relationship was found to existbetween cardiac output (Q) and body weight (W(,b)): Q(' )=(' )1.99(W(,b))('0.50). Stroke volumes ranged from 1.03 to 1.85 ml with larger animals possessing larger stroke volumes;During aerial exposure, cardiac output declined immediately; stroke volume decreased by a nearly proportional amount while heart rate decreased only moderately. At the same time, mean arterial pressure usually increased. This suggested the possibility of blood re-distribution during aerial exposure;Microsphere studies in submerged animals showed that blood flow to selected tissues correlated very closely with reported values for oxygen uptake of the isolated tissues. During aerial exposure, blood flow decreased to many of the tissues examined. Blood flow increased 2 to 3 x to the mantle tissue. This suggests the possibility that the mantle may become important as an accessory gas exchange organ during aerial exposure.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Darwin Dwayne Jorgensen
Jorgensen, Darwin Dwayne, "Cardiac output and its distribution in the intertidal mollusc, Haliotis cracherodii " (1981). Retrospective Theses and Dissertations. 7435.