First Advisor

Stanley S. Hillman

Term of Graduation

Summer 1997

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Biology






Body fluids -- Regulation, Bufo marinus -- Physiology, Bullfrog -- Physiology



Physical Description

1 online resource (v, 102 pages)


The capillary filtration coefficient (CFC) and isovolumetric capillary pressure (Pci) were measured in Bufo marinus and Rana catesbeiana, using a gravimetric technique on an in vitro preparation while perfusing with Ringers and 0.1 g·100 ml-1 bovine serum albumin Estimates of pre- and post-capillary resistance were obtained from Bufo; the post- to pre-capillary resistance ratio was found to be 0.18, which was used to estimate capillary pressure. CFC was found to be 6.68 ± 0.51 and 5.07 ± 0.23 ml·min-1·kg-1·mmHg-1 and Pci was found to be 7.4 and 6.3 mmHg in Bufo marinus and Rana catesbeiana, respectively. An in vivo estimate of isovolumetric capillary pressure, after correcting for osmotic pressures of plasma proteins, would be approximately 11.5 and 9.3 mmHg for Bufo marinus and Rana catesbeiana, respectively. Using this resistance ratio, resting capillary pressures were estimated, based on published data, to be 10.8 and 11.3 mmHg for Bufo marinus and Rana catesbeiana, respectively. These results show that both of these anuran amphibians have a very high CFC, indicating a highly permeable capillary membrane, but they do not begin to filter until very high hydrostatic pressures are reached. Further, the differences between Bufo marinus and Rana catesbeiana indicate that the reversal of Starling forces from net filtration to net absorption during hypovolemia would occur sooner in Bufo than in Rana. This is consistent with the superior dehydration tolerance seen in toads versus frogs.


In Copyright. URI: This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Persistent Identifier

Included in

Biology Commons