First Advisor

Stanley S. Hillman

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Biology






Osmoregulation, Cardiovascular system, Bufo marinus -- Physiology, Bullfrog -- Physiology



Physical Description

1 online resource, (49p.)


The mean circulatory filling pressure (MCFP), vascular compliance (C) and unstressed volume (USV) were measured in Bufo marinus and Rana catesbeiana, using an in vivo preparation. Capacitance curves were constructed by varying total vascular volume and then measuring MCFP. These capacitance curves enable the extrapolation of USV and the measurement of vascular compliance. The MCFP, C, and USV were 8.6 ± 0.2 (mmHg), 3.7 (ml· mmHg-1 · kg- 1 ) and 2.5 (ml), respectively, in B. marinus. The MCFP, C, and USV were 9.5 ± 0.1 (mmHg), 2.2 (ml· mmHg-1 · kg- 1 ) and 14.2 (ml), respectively, in R. catesbeiana. In addition, C measurements were determined from capacitance curves constructed at extreme hypovolemic states, for both amphibians. The C changed from 3.7 to 6.5 (ml· mmHg-1 · kg-1 ) in B. marinus, during hypovolemia. The C changed from 2.2 to 2.4 (ml· mmHg-1 · kg-1 ) in R. catesbeiana, during hypovolemia. The whole body vascular compliance increased more in B. marinus, and was higher at all vascular volume perturbations. The higher compliance at lower vascular volumes, in Bufo marinus, supports the idea of a greater dehydration tolerance in the terrestrial anuran compared to the aquatic anuran, Rana catesbeiana.


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