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Full-Text Articles in Physiology
Control Of Blood Volume Following Hypovolemic Challenge In Vertebrates: Transcapillary Versus Lymphatic Mechanisms., Stanley S. Hillman, Robert C. Drewes, Michael S. Hedrick
Control Of Blood Volume Following Hypovolemic Challenge In Vertebrates: Transcapillary Versus Lymphatic Mechanisms., Stanley S. Hillman, Robert C. Drewes, Michael S. Hedrick
Biology Faculty Publications and Presentations
Anurans have an exceptional capacity for maintaining vascular volume compared with other groups of vertebrates. They can mobilize interstitial fluids via lymphatic return at rates that are ten-fold higher than mammals. This extraordinary capacity is the result of coordination of specialized skeletal muscles and pulmonary ventilation that vary volume and pressure of subcutaneous lymph sacs, thus moving lymph to dorsally located lymph hearts that return lymph to the vascular space. Variation in the capacity to mobilize lymph within anurans varies with the degree of terrestriality, development of skeletal muscles, lung volume and lung compliance, and lymph heart pressure development. This …
The Significance Of Hypovolemia In Dehydrational Death In Anurans, Peter Blair Kimmel
The Significance Of Hypovolemia In Dehydrational Death In Anurans, Peter Blair Kimmel
Dissertations and Theses
The importance of hypovolemia in dehydrational death was assessed in two anuran species. Xenopus laeyis, a species which experiences a significant reduction in circulating plasma volume with dehydration, was used to evaluate the role of sympathetic reflex compensation in hypovolemia. Adrenergic blockade with propranolol or phenoxybenzamine produced no significant reduction in dehydration tolerance in this species, although β-blockade with propranolol appeared to have a minor effect. The role of hypovolemic shock in the terminal circulatory collapse that precedes death in dehydrating anurans was investigated in the toad, Bufo marinus. The activity of lysosomal proteinases (cathepsins) was used as an indicator …
Effects Of Dehydration On Hemoglobin Oxygen Affinity And Blood Cell Volume In Two Anurans, Andrew Christopher Zygmunt
Effects Of Dehydration On Hemoglobin Oxygen Affinity And Blood Cell Volume In Two Anurans, Andrew Christopher Zygmunt
Dissertations and Theses
Two aspects of possible adaptation in cardiovascular performance caused by increased plasma electrolytes were examined. Cells in anisotonic plasma may either act as osmometers or volume regulate. Blood flow rate is dependent upon cell viscosity, which in turn is a consequence of cell volume and membrane deform-ability. Cell volume changes which increase membrane deform-ability will thus potentially extend the limits of dehydration tolerance. It was found in R. catesbeiana and B. marinus that red blood cell is maintain constant volume during dehydration. Cells in vitro initially lose water, but then sodium, potassium and water move into the cell. Cell viscosity …