scholarly journals Effects of Cold Exposure on Oxygen Consumption, Ventilation and Interclavicular Air-Sac Gases in the Little Penguin(Eudyptula Minor)

1990 ◽  
Vol 154 (1) ◽  
pp. 397-405
Author(s):  
HEGE JOHANNESEN ◽  
STEWART C. NICOL
Keyword(s):  
Oxygen Consumption ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Tidal Volume ◽  
Cold Exposure ◽  
Strong Correlation ◽  
Respiratory Frequency ◽  
Oxygen Extraction ◽  
Ambient Temperatures ◽  
Little Penguin

Oxygen consumption (VO2), tidal volume, respiratory frequency and the composition of the gas in the interclavicular air sac were measured in the little penguin Eudyptula minor (Forster) at ambient temperatures (Ta) of 5 and 20 °C. VO2 increased from 14.60 ml O2 kg−1 at 20°C to 18.29 ml O2 kg−1 min−1 at 5 °C. However, the elevated atVO2 the low Ta was not matched by a similar rise in total inspiratory ventilation (Vi). The ventilatory requirement (Vi/VO2) thus decreased from 0.5751 mmol−11 at 20°C to 0.4401 mmol−1 at 5°C. An increased gas exchange efficiency during cold exposure was also shown by the composition of the gas in the interclavicular air sac. PO2 decreased from 11.95 kPa at 20°C to 10.24kPa at 5°C, while the corresponding increase in PCO2 was from 6.61 to 7.50 kPa. Oxygen extraction, calculated from VO2, Vi and O2 content of the inspired air, increased from 24.60% at 20°C to 31.04% at 5°C. Oxygen extraction calculated from the O2 contents of inspired air and interclavicular air—sac gas was 38.73 % at 20°C and 47.18% at 5°C. The results confirm previous findings for the little penguin which showed a decrease in the ventilatory requirement with increasing oxygen uptake. However, the improved gas exchange efficiency during cold exposure and the strong correlation found between oxygen extraction and oxygen consumption have not been demonstrated previously for this species.

Effect of residence at altitude on the perception of breathlessness on return to sea level in normal subjects

1993 ◽  
Vol 84 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Rachel C. Wilson ◽  
W. L. G. Oldfield ◽  
P. W. Jones
Keyword(s):  
Oxygen Consumption ◽  
Tidal Volume ◽  
Sea Level ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Cycle Ergometer ◽  
Respiratory Frequency ◽  
Borg Scale ◽  
Oxygen Pulse ◽  
Ventilatory Equivalent

1. The effect of residence at altitude on the perception of breathlessness after return to sea level was examined in normal subjects. Breathlessness (Borg scale), minute ventilation, respiratory frequency, tidal volume, ‘oxygen pulse’ (oxygen consumption/heart rate) and the ventilatory equivalent for oxygen (minute ventilation/oxygen consumption) were measured at exercise (cycle-ergometer) during 5 months of training before 4 weeks at 4000 m and during the 6 month period after return to sea level. 2. There was no change in the subjects' pattern of breathing (respiratory frequency and tidal volume) or ‘oxygen pulse’ after the period at altitude (P = 0.0001). The ventilatory equivalent for oxygen was increased at all work rates after the period at altitude (P = 0.02). This ratio was slightly lower after 6 weeks and had returned to normal by 6 months (P = 0.4). 3. During training there was no change in breathlessness score (P = 0.6). On return to sea level, breathlessness score relative to ventilation was reduced (P = 0.0001). This was maintained for at least 6 weeks, but not as long as 6 months. 4. This study has demonstrated that, in normal subjects, the otherwise stable and reproducible relationship between breathlessness and ventilation may be disrupted for several weeks by factors other than lung disease. 5. The mechanism responsible for this is not clear, but the observations are consistent with the hypothesis that prior experience of breathlessness may condition subsequent estimates of breathlessness.

Terrestrial life in isopods: evolutionary loss of gas-exchange and survival capability in water

1993 ◽  
Vol 71 (7) ◽  
pp. 1372-1378 ◽  
Author(s):  
Barbara E. Taylor ◽  
Thomas H. Carefoot
Keyword(s):  
Oxygen Consumption ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Fresh Water ◽  
Porcellio Scaber ◽  
Progressive Decline ◽  
Terrestrial Species ◽  
Terrestrial Isopods ◽  
Armadillidium Vulgare ◽  
Terrestrial Life

Survival and oxygen uptake in air and water were investigated in four species of terrestrial isopods, Armadillidium vulgare Latreille, 1804, Porcellio scaber Latreille, 1804, Oniscus asellus Linné, 1758, and Ligia pallasii Brandt, 1833, to compare the degree of vestigial adaptation to aquatic existence versus adaptation to terrestrial existence. Most submerged A. vulgare, P. scaber, and O. asellus died by 18 h, whether in fresh water or isosmotic seawater. Ligia pallasii lived for almost 2 d in fresh water and for at least 25 d in seawater (none died during this time). Oxygen uptake in water was 44 – 66% that in air for the three fully terrestrial species, and 160% that in air for the semiterrestrial L. pallasii. Oxygen consumption of submerged A. vulgare (representative of fully terrestrial forms) declined to 50% after 14 h and to 17% by 24 h, by which time the animals were clinically dead. In comparison, L. pallasii's aquatic oxygen consumption was maintained at normal or higher levels for at least 3 d. All species could survive several hours of immersion in fresh water, sufficient to withstand temporary rain deluge. Ligia pallasii's superior capabilities to survive and respire in seawater reflect its greater similarity to aquatic ancestors, and an evolutionary series showing progressive decline in survival and gas-exchange capability in water would be as follows: L. pallasii > O. asellus > P. scaber ≥ A. vulgare.

scholarly journals ARRHYTHMIC BREATHING, APNEA AND NON-STEADYSTATE OXYGEN UPTAKE IN HIBERNATING LITTLE BROWN BATS (MYOTIS LUCIFUGUS)

1990 ◽  
Vol 149 (1) ◽  
pp. 395-406
Author(s):  
DONALD W. THOMAS ◽  
DANIELLE CLOUTIER ◽  
DANIEL GAGNÉ
Keyword(s):  
Oxygen Consumption ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Breathing Pattern ◽  
Adaptive Strategies ◽  
Open Circuit ◽  
Myotis Lucifugus ◽  
O2 Uptake ◽  
Closed Glottis ◽  
Little Brown Bats

We measured the breathing pattern and oxygen consumption of hibernating little brown bats {Myotis lucifugus) in open- and closed-circuit metabolic chambers. At 5°C, hibernating M. lucifugus showed bouts of ventilation lasting on average 1.24min and separated by periods of apnea lasting on average 47.59min. The bats consumed 0.014 ml O2g−1 during ventilation bouts and 0.002 ml g−1 during apnea. The total O2 uptake was 0.016 ml g−1 for a complete ventilationapnea cycle, giving a Vo2 of 0.020 ml g−1 h−11. This value is considerably lower than most values previously published for Myotis spp. and we suggest that studies using open-circuit systems that did not account for the intermittent nature of gas exchange during hibernation may be in error. Based on the dimensions of the respiratory tract, we estimate that 0.026 ml O2g−1h−1 and 0.009mlCO2g−1h−1 could diffuse down the tract if the glottis was open. The low O2 uptake during apnea indicates that the glottis was closed. If CO2 retention acts to depress metabolism in hibernators, a closed glottis and arrhythmic breathing may be adaptive strategies in hibernation.

Quantifying Compound Aging Resistance at Service (Ambient) Temperatures

2009 ◽  
Vol 82 (1) ◽  
pp. 121-130
Author(s):  
Edward R. Terrill ◽  
James T. Lewis
Keyword(s):  
Oxygen Consumption ◽  
Service Life ◽  
Oxygen Uptake ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Tensile Elongation ◽  
Ambient Temperatures ◽  
Rubber Compounds ◽  
Consumption Rates ◽  
The Stability

Abstract Oxygen consumption rates were measured on natural rubber compounds with varying levels of a standard antioxidant package. The oxygen consumption rate measurements were performed at temperatures between 20 °C and 80 °C. The results elucidated the mechanism of antioxidants, including their pro-oxidant effects. The pro-oxidant effect dwindled with time. Integrated oxygen uptake results were calculated from repetitive oxygen consumption rate measurements. Integrated oxygen uptake time temperature master curves with empirical shift factors were combined with elongation-tobreak data to monitor the extent of aging. The stability of the compounds at service life temperatures could be quantified by combining the integrated oxygen uptake shift factors with the tensile elongation-to-break data; thereby to produce an elongation-to-break master curve at service life temperatures.

Influence of luminal nutrient composition on hemodynamics and oxygenation in developing intestine

1992 ◽  
Vol 263 (2) ◽  
pp. G254-G260 ◽  
Author(s):  
K. D. Crissinger ◽  
D. L. Burney
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Vascular Resistance ◽  
Corn Oil ◽  
Age Groups ◽  
Older Age ◽  
Intestinal Blood Flow ◽  
Oxygen Extraction ◽  
Age Related

Age-related differences in the intestinal hemodynamic and oxygenation responses to carbohydrate, protein, and lipid were studied in 1-day-, 3-day-, 2-wk-, and 1-mo-old piglets. A branch of the mesenteric vein draining an isolated loop of jejunoileum was used to measure intestinal blood flow, arteriovenous oxygen content difference, and venous and capillary pressure and to calculate oxygen uptake and vascular resistance. Fractionated intestinal flow was measured with radiolabeled microspheres. Measurements were made before and after luminal placement of either 5% glucose, 2.3% casec, or 5% corn oil. In 1-day-old animals, unlike all older age groups, total intestinal blood flow and vascular resistance were unchanged by any nutrient. Fractionated flow to the mucosa/submucosa levels did, however, increase in the intestine of 1-day-old piglets to a similar extent as that in older age groups. Placement of lipid or protein into the lumen led to increased oxygen uptake in all age groups, whereas carbohydrate absorption resulted in no increase in intestinal oxygen consumption in 1- and 3-day-old animals. In 1-day-olds, the increased oxygen consumption was achieved by enhanced oxygen extraction with no change in total blood flow, whereas all other groups demonstrated increases in blood flow and/or oxygen extraction. Compared with a mixed meal, oxygen consumption was not significantly greater for an individual nutrient component.

Thermoregulation and ventilation in the tawny frogmouth, Podargus strigoides: a low-metabolic avian species

1999 ◽  
Vol 47 (2) ◽  
pp. 143 ◽  
Author(s):  
Claus Bech ◽  
Stewart C. Nicol
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Thermal Conductance ◽  
Respiratory Frequency ◽  
Mean Body Temperature ◽  
Ambient Temperatures ◽  
A Value ◽  
Ventilatory Volume

Oxygen consumption (VO2) and body temperature (Tb) were measured during daytime (corresponding to the normal resting phase) in the tawny frogmouth (Podargus strigoides, mean body mass of 341 g) at ambient temperatures (Ta) between -1ºC and 30ºC. Mean body temperature (over this range of Ta) was 37.8ºC and there was only a small (0.4ºC), and insignificant, day-night variation in Tb. Mean VO2 within thermoneutrality (25-30ºC) was 0.59 mL O2 g-1 h-1 , corresponding to a basal metabolic rate (BMR) of 3.32 W kg-1 . This value is only 61% of the predicted value for a non-passeriform bird. The minimal thermal conductance attained at Ta below thermoneutrality was 0.156 W kg-1 ºC-1, a value which is very close to the allometrically predicted value. The relatively low VO2 was paralleled by a low total ventilatory volume. This, in turn, was mainly the result of a low respiratory frequency (10.2 breaths min-1, only 52% of that expected for a similar-sized bird) whereas tidal volume (6.6 mL [BTPS]) was 107% of the expected value. Thus, our results suggest that the changing ventilatory needs during the evolution of the low VO2 in the tawny frogmouth have been met primarily by changes in respiratory frequency.

Mechanisms Controlling Dormancy in the Arid Zone Grass Aristida contorta. I. Physiology and Mechanisms of Dormancy

1974 ◽  
Vol 22 (4) ◽  
pp. 635 ◽  
Author(s):  
JJ Mott
Keyword(s):  
Gas Exchange ◽  
Oxygen Uptake ◽  
High Temperatures ◽  
Arid Zone ◽  
Ambient Temperatures ◽  
Oxidizing Agents

Two dormancy mechanisms are evident in young A. contorta grain. One is an after-ripening requirement of the embryo, and can be satisfied by storage at ambient temperatures; the second is associated with the hull and requires prolonged periods of high temperatures before germination can take place. The dormancy imposed by the hull is not controlled by a leachable inhibitor, but germination can be stimulated by oxidizing agents or by the removal of small sections of the hull directly over the embryo. The oxygen uptake of dormant grain is very low, but non-dormant grain, or dormant grain with the hull removed, shows a much higher uptake. The possibility remains that there is a mechanical restriction of gas exchange by the hull, the hull of non-dormant grain being more permeable than that of dormant grain.

OXYGEN SUPPLY AND PERFORMANCE IN PEROMYSCUS: COMPARISON OF EXERCISE WITH COLD EXPOSURE

1967 ◽  
Vol 45 (3) ◽  
pp. 543-549 ◽  
Author(s):  
Neri P. Segrem ◽  
J. S. Hart
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Body Temperature ◽  
Oxygen Uptake ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Cold Exposure ◽  
Temperature Regulation ◽  
Oxygen Supply ◽  
And Performance

Oxygen consumption, heart rate, and body temperature were measured at temperatures ranging from 27 °C to −28 °C and at oxygen partial pressure [Formula: see text] levels from 60 to 196 mm Hg. Temperature regulation and O2 uptake were progressively limited by reduction of [Formula: see text]. Limitation of O2 consumption by O2 supply was similar to that seen during exercise. The highest oxygen uptake during exposure to cold was greater than during exercise at the higher levels of [Formula: see text].

Metabolism, Respiration and Evaporative Water Loss in the Australian Hopping-Mouse Notomys Alexis (Rodentia: Muridae).

1979 ◽  
Vol 27 (2) ◽  
pp. 195 ◽  
Author(s):  
PC Withers ◽  
AK Lee ◽  
RW Martin
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Tidal Volume ◽  
Water Loss ◽  
Minute Volume ◽  
Evaporative Water Loss ◽  
Moist Air ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Dry Air

Resting oxygen consumption and total evaporative water loss were determined for N. alexis at ambient temperatures of 20, 28 and 33 deg C in dry air. The minimum rate of oxygen consumption was 0.61 ml min-1 at 33 deg C, and minimum total evaporative water loss was 4.75% body mass day-1 at 28 deg C. Respiration frequency, tidal volume and respiratory minute volume were determined for N. alexis at ambient temperatures of 20, 28 and 33 deg C in air of low or high relative humidity. Minimum values were obtained at 28 deg C and low RH for respiratory minute volume and tidal volume, and at 28 deg C and high RH for respiratory frequency. Expired air temperature of N. alexis at these temperatures was lower than or similar to ambient for mice in air of low RH, but was higher than or similar to ambient at high RH. Respiratory evaporative water loss, calculated from the previous data, was greatest for mice in dry air at 33 deg C, and least in moist air at 33 deg C. Cutaneous evaporative water loss made up about 40-60% of the total evaporative water loss for mice in dry air. The rates of total evaporative water loss were clearly reflected in the manner of body temperature regulation at high ambient temperatures. Hopping-mice in moist air at 28 and 33 deg C became hyperthermic, whereas mice in dry air showed only slight increases in body temperature. The significance of these data to hopping-mice in the field was discussed.

Exercising with and Without Lungs: I. The Effects of Metabolic Cost, Maximal Oxygen Transport and Body Size on Terrestrial Locomotion in Salamander Species

1988 ◽  
Vol 138 (1) ◽  
pp. 471-485 ◽  
Author(s):  
ROBERT J. FULL ◽  
BRUCE D. ANDERSON ◽  
CASEY M. FINNERTY ◽  
MARTIN E. FEDER
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Body Size ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Metabolic Cost ◽  
Locomotor Performance ◽  
Terrestrial Locomotion ◽  
Ambystoma Laterale ◽  
Salamander Species

To whom offprint reprints should be addressed. Metabolic cost, oxygen consumption (MO2, respiratory structure and body size interact to determine the capacity of salamanders for terrestrial locomotion. Salamanders respiring via both lungs and skin, Ambystoma laterale and A. tigrinum, or with skin alone, Desmognathus ochrophaeus and D. quadramaculatus, attained a steady-state MO2 during exercise in a treadmill respirometer. Endurance was correlated with the speed at which maximal MO2, was attained (VMO2.max). Low aerobic costs of transport (60–80% lower than reptiles of similar mass) increased VMO2.max. However, in lungless salamanders a low maximum MO2 decreased VMO2.max significantly. MO2 increased only 1.6- to 3.0-fold above resting rates in active lungless salamanders, whereas it could increase 3.5- to 7.0-fold in active lunged salamanders. Lungless salamanders attained maximal MO2 at half to one-tenth the speed of lunged animals. Lungless salamanders fatigued in 20 min or less at speeds that lunged salamanders could sustain for 1–2 h. Body size also affected the capacity for oxygen uptake during activity and locomotor performance. The large lungless salamander D. quadramaculatus attained maximum MO2 even at its lowest rate of travel. Cutaneous gas exchange does not provide lungless salamanders with gas transport capacities found in lunged animals. However, only small increases in MO2 may be required for modest levels of activity.

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