Pulmonary gas exchange during intermittent ventilation in the American alligator.
The present study characterized pulmonary gas exchange in the American alligator, Alligator mississipiensis during ventilation and apnea at a body temperature (Tb) of 25 degrees C. Pulmonary gas exchange parameters were measured on a breath-by-breath basis utilizing a computer-assisted data acquisition system. In addition, paired blood samples were analyzed from left and right atrium during ventilation and voluntary apneas (1, 2, 5 and 10 min). Measurements of lung PO2 and PCO2 indicated that as apnea progressed, CO2 flux into the lung decreased rapidly while O2 was continuously removed at a constant and steady rate. The reduction in VCO2 resulted in a decrease in R (less than 0.4). Blood gas measurements indicated that the pulmonary arterial-pulmonary venous PCO2 difference, (Ppa-Ppv)CO2 was 4.9 +/- 0.9 mmHg during ventilation, decreased and became negative within 2 min of apnea, reaching -3.9 +/- 0.6 mmHg after 10 min. It is postulated that during apnea the Haldane effect accounts for both the blood gas behavior across the lung and insures a continued CO2 flux into the lung during apnea.
Hicks
J W
JW
Physiological Research Laboratory, Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92023.
White
F N
FN
D000489:Alligators and Crocodiles / Q000502:physiology*; D000818:Animals; D001692:Biological Transport; D002245:Carbon Dioxide / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011659:Pulmonary Gas Exchange; D012119:Respiration / Q000502:physiology
D002245:Carbon Dioxide; D010100:Oxygen