Cardiovascular dynamics inCrocodylus porosus breathing air and during voluntary aerobic dives

  title={Cardiovascular dynamics inCrocodylus porosus breathing air and during voluntary aerobic dives},
  author={Gordon Grigg and Kjell Johansen},
  journal={Journal of Comparative Physiology B},
SummaryPressure records from the heart and out-flow vessels of the heart ofCrocodylus porosus resolve previously conflicting results, showing that left aortic filling via the foramen of Panizza may occur during both cardiac diastole and systole. [] Key Result Filling of the left aorta during diastole, identified by the asynchrony and comparative shape of pressure events in the left and right aortae, is reconciled more easily with the anatomy, which suggests that the foramen would be occluded by opening of…
It is clear from the present work that low systemic blood pressure is a factor of crucial importance in establishing left aortic flow.
The sub-pulmonary conus and the arterial anastomosis as important sites of cardiovascular regulation in the crocodile Crocodylus porosus
We present evidence to support the hypothesis that the arterial anastomosis and the cogteeth-like valves located in the sub-pulmonary conus in the right ventricle are important sites of
Delayed depolarization of the cog-wheel valve and pulmonary-to-systemic shunting in alligators.
Evidence is provided that phasic contraction of the cog-wheel valve muscle controls shunting, that nervous and cholinergic stimulation can alter the delay and strength of valve depolarization and that this can affect the propensity to shunt.
Central Cardiovascular Dynamics in Reptiles
The ability of the heart to keep hypoxic (“venous”) blood that returns to the heart via the large systemic veins separate from the oxygenated blood from gills and/or lungs increases the efficiency of
Ring around the heart: an unusual feature of the crocodilian central circulatory system.
RAo section in alligators and caimans revealed marked effects on growth and energy conversion but too few animals were available to claim statistical significance, indicating little selective advantage for retention of bulk flow of venous blood to the body.
Does the left aorta provide proton-rich blood to the gut when crocodilians digest a meal?
The findings do not support the hypothesis that a R–L shunt serves to deliver CO2 for the gastrointestinal system after feeding in crocodilians, and blood in the left aorta of American alligators does not contain elevated PCO2 levels during digestion.
The role of the pericardium and the effects of adrenaline and changes in oxygen tension on the performance of an in situ perfused crocodile heart
Higher flows were generated at low filling pressures during the input pressure challenge as a result of an increase in the sensitivity of the Starling response.
Feeding alters blood flow patterns in the American alligator (Alligator mississippiensis).
Surgical removal of right-to-left cardiac shunt in the American alligator (Alligator mississippiensis) causes ventricular enlargement but does not alter apnoea or metabolism during diving
While surgical removal of R–L shunt in American alligators causes considerable changes in cardiac morphology similar to aortic banding in mammals, its removal does not affect the respiratory pattern or metabolism of alligators, and it appears probable that the low metabolic rate of reptiles allows for normal aerobic dives.
The Right‐to‐Left Shunt of Crocodilians Serves Digestion
It is hypothesized 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.


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In case of Crocodylus, by analysis of blood, the author came to a conclusion that during normal respiration the foramen panizza serves for the passage of blood in both directions during the different phases of the cardiac cycle.
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The crocodilian heart is compared with, and seen as an advancement of, the heart of non‐crocodilian reptiles, and the varanid ventricle is re‐examined, as it appeared to contain many crocodilian features, along with the ophidian characteristics described previously.
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The hypothesis that external hypoxia would result in a reduction of preferred body temperature in ectotherms with high preferred body temperatures is confirmed, now confirmed in several species.