Oxygen Transport by the Circulatory System of the Green Iguana (Iguana Iguana) at Different Body Temperatures

1966 ◽  
Vol 44 (1) ◽  
pp. 77-92
Author(s):  
VANCE A. TUCKER
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Venous Blood ◽  
Circulatory System ◽  
Body Temperatures ◽  
Iguana Iguana ◽  
Arterial Blood ◽  
Percentage Saturation ◽  
The Right

1. Oxygen consumption, stroke volume, heart rate and the difference in oxygen contents of arterial and venous blood (AV difference) were measured in the resting iguana at body temperatures of 20, 30 and 38° C. Oxygen consumption increased by a factor of 4.4 as temperature changed from 20 to 38° C. This increase was accomplished by a decrease in stroke volume by a factor of 0.5, and increases in heart rate and AV difference by factors of 4.1 and 2.2, respectively. 2. During activity increases in oxygen consumption at a given temperature were accompanied by increases in heart rate and AV difference, but stroke volume did not change consistently. 3. The percentage saturation of arterial blood with oxygen in the iguana may differ in the right and left systemic arches. In some lizards, both arches carried equally saturated blood, but in others the left arch carried blood containing less oxygen than the right arch. 4. An hypothesis is presented concerning the function of the double systemic arches and incompletely divided ventricles of lizards. These structures may be a device for permitting increased cardiac output associated with thermoregulation to bypass the lungs while maintaining a supply of well-oxygenated blood to the head. 5. Data on oxygen capacity, percentage saturation of blood with oxygen, haematocrit and pH of iguana blood are included in this study.

Cardiac Output in the Large Cephalopod Octopus Dofleini

1965 ◽  
Vol 42 (3) ◽  
pp. 475-480
Author(s):  
KJELL JOHANSEN
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Work ◽  
Free Swimming ◽  
Blood Samples ◽  
Fick Principle ◽  
Arterial Blood ◽  
Percentage Saturation ◽  
Intravascular Catheters

The cardiac output in Octopus dofleini has been measured, making use of the Fick principle. The measurements were made on intact animals, resting or free-swimming, after previous chronic implantation of intravascular catheters for collection of blood samples. The respiratory exchange was measured with a specially designed respirometer. In addition to cardiac output the following parameters were measured or computed: oxygen consumption; oxygen tension, oxygen content and percentage saturation of venous and arterial blood; arterial pressure; heart rate; stroke volume and stroke work. A detailed discussion of the results obtained is limited by the lack of comparable information for other invertebrates.

Initial hemodynamic responses to mild exercise in trained dogs

1965 ◽  
Vol 20 (3) ◽  
pp. 437-442 ◽  
Author(s):  
Harold Smulyan ◽  
Richard P. Cuddy ◽  
William A. Vincent ◽  
Udomporn Kashemsant ◽  
Robert H. Eich
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Right Atrium ◽  
Initial Reaction ◽  
Hemodynamic Responses ◽  
Heart Rates ◽  
Infusion Method ◽  
The Right

The transient changes in cardiac output at the onset of mild exercise were measured in dogs trained to walk on a treadmill. Cardiac output was obtained using a krypton 85 infusion method, which permitted frequent determinations of flow. The first go sec of exercise were marked by a prompt rise and overshoot of heart rate and cardiac output, whereas increases in stroke volume occurred later after the onset of exercise, and to a lesser extent than heart rate. At rest, the right atrium was electrically driven at rates slightly faster than heart rates attained spontaneously with exercise and the studies repeated. Changes in cardiac output with exercise were similar to those in unpaced animals, but when the heart rate was fixed stroke volume increased immediately. These studies show a consistent rise in heart rate and cardiac output in the initial reaction to exercise, but when the prompt rise in heart rate was prevented by pacing from the right atrium, increases in stroke volume provided a comparable response in cardiac output. krypton 85; cardiac output; stroke volume; pacing of heart; oxygen consumption Submitted on September 23, 1964

Effects of exercise on heart output of the dog

1961 ◽  
Vol 16 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Michael D. Bailie ◽  
Sid Robinson ◽  
Howard H. Rostorfer ◽  
Jerry L. Newton
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Carotid Artery ◽  
Stroke Volume ◽  
Minute Volume ◽  
Open Circuit ◽  
Work Rate ◽  
Left Carotid Artery ◽  
The Right ◽  
Oxygen Difference

Effects of varying rates of work on the heart output of healthy young dogs were determined by the direct Fick method. Blood was sampled simultaneously through a polyethylene catheter in the right ventricle and an inlying needle in the left carotid artery. Heart rates were determined from right ventricular pressure recordings. Oxygen consumption was determined by the open-circuit method. Oxygen consumption of the dog was linearly related to work rate in runs on the treadmill at 5.6, 9.6 and 12.9 km/hr. up an 18% grade. Minute volume of the heart, arteriovenous oxygen difference, heart rate and stroke volume were found to increase with increasing metabolic rate. The average stroke volume in the hardest work rate was 82% greater than the average resting value. An animal whose activity had been greatly restricted for 3 months showed a 62% increase in stroke volume from rest to running on the treadmill at 9.6 km/hr. up an 18% grade. The data show that a substantial increase in stroke volume in work must necessarily occur in order to account for the observed increase in minute volume. Submitted on May 10, 1960

scholarly journals THE OXYGEN AND CARBON DIOXIDE CONTENT OF ARTERIAL AND OF VENOUS BLOOD IN NORMAL INDIVIDUALS AND IN PATIENTS WITH ANEMIA AND HEART DISEASE

1919 ◽  
Vol 30 (3) ◽  
pp. 241-257 ◽  
Author(s):  
George A. Harrop
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Oxygen Content ◽  
Normal Values ◽  
Normal Individual ◽  
Venous Blood ◽  
Carbon Dioxide Content ◽  
Arterial Blood ◽  
Percentage Saturation ◽  
Normal Individuals

1. The oxygen content of venous and of arterial blood from fifteen essentially normal individuals at rest in bed has been determined. 2. The percentage saturation of the arterial blood has varied between 100 and 94.3. The average is 95.5 per cent. 3. The oxygen consumption has varied between 2.6 and 8.3 volumes per cent. 4. The oxygen content and the percentage saturation of arterial blood taken at close intervals from three different peripheral arteries of a normal individual have shown values agreeing within the limits of error. Analyses of the blood gases of a normal individual, at rest and after exercise, have shown a lowering of the percentage oxygen saturation of the arterial blood and a diminished carbon dioxide content after exercise. 5. In three persons with severe anemia the saturation of the arterial blood has not differed from the normal. Very low absolute values were found for the oxygen content of the venous blood, but the normal oxygen consumption has been maintained. 6. The carbon dioxide content of the arterial blood from ten normal individuals has varied between 54.7 and 44.6 volumes per cent. That of the venous blood has varied between 60.4 and 48.3 volumes per cent. 7. No deviations from the normal values for oxygen and carbon dioxide were found in venous and arterial blood from cardiac patients without arrhytiunias, well compensated, and at rest in bed. 8. A series of determinations has been made upon nine cardiac patients with varying degrees of decompensation. The percentage oxygen saturation of the arterial blood on admission was abnormally low in seven of these cases. With the return to compensation and with the clearing up of pulmonary symptoms, the percentage saturation of the arterial blood returned to normal in four of them. 9. In a case of long standing mitral endocarditis with auricular fibrillation it remained low over a period of I month of observation. 10. In a case of chronic myocarditis secondary to emphysema and chronic bronchitis, it remained low over the period of observation. 11. Normal values for the percentage saturation of the arterial blood were found in two individuals with decompensated aortic disease but without physical signs of extensive pulmonary involvement. 12. The oxygen consumption tended to be high in individuals with cardiac disease during the periods of marked decompensation and to be lower as compensation was regained. 13. The data presented indicate that at least in many circulatory diseases during decompensation, particularly when there are physical signs of pulmonary congestion, there is a disturbance of the pulmonary exchange, as indicated by the lowering of the percentage saturation of the arterial blood with oxygen.

Regulation of arterial blood pressure in Australian tiger snakes

1978 ◽  
Vol 75 (1) ◽  
pp. 65-79 ◽  
Author(s):  
H. B. Lillywhite ◽  
R. S. Seymour
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Complete Recovery ◽  
Pressure Control ◽  
Pressure Regulation ◽  
Body Temperatures ◽  
Heating And Cooling ◽  
Arterial Blood ◽  
Preferred Temperatures ◽  
Head Up Tilt

1. Blood pressure was measured in the dorsal aorta of restrained, unanaesthetized tiger snakes (Notechis scutatus) at different body temperatures during graded, passive tilt. Aortic blood pressure in horizontal snakes showed no significant change over a range of body temperatures between 18 and 33 degrees C (mean of measurements on 16 snakes = 42.2 +/− I.98 mmHg), while heart rate increased logarithmically (Q10 approximately 2.5). Blood pressure was stable during heating and cooling between body temperatures of 15 and 30 degrees C, but the pressure was 10--50% higher during heating than during cooling. 2. Head-up tilt usually caused a brief fall in pressure at heart level followed by partial or complete recovery and tachycardia. At the cessation of tilt, there was a characteristic overshoot of the blood pressure followed by readjustment to control (pretilt) levels. Head-down tilt typically increased pressure which then either stabilized or returned toward pretilt levels. Heart rate changes during head-down tilt were not consistent in direction or magnitude. Stabilized pressures at mid-body usually increased following head-up tilt and decreased following head-down tilt, indicating physiological adjustment to posture change. Blood pressure control was evident at body temperatures ranging from 10 to 38 degrees C, but was most effective at the higher and behaviourally preferred temperatures. 3. Propranolol lowered heart rate but did not influence pressure in horizontal snakes. During head-up tilt propranolol eliminated or reduced tachycardia and sometimes reduced the efficacy of pressure compensation for tilt. Phentolamine increased heart rate, lowered blood pressure, and eliminated pressure regulation during tilt. The results suggest that sympathetically mediated reflexes assist central blood pressure regulation in the tiger snake, with vasomotor adjustments having greater importance than changes in heart rate.

MAINTENANCE OF OXYGEN CONSUMPTION IN RESTING SILURUS GLANIS AT DIFFERENT LEVELS OF AMBIENT OXYGENATION

1989 ◽  
Vol 143 (1) ◽  
pp. 305-319 ◽  
Author(s):  
JEAN FORGUE ◽  
BERNARD BURTIN ◽  
JEAN-CHARLES MASSABUAU
Keyword(s):  
Oxygen Consumption ◽  
Venous Blood ◽  
Blood Flow Rate ◽  
Binding Characteristics ◽  
Silurus Glanis ◽  
Arterial Blood ◽  
O2 Partial Pressure ◽  
O2 Extraction ◽  
O2 Concentration ◽  
Mechanisms Of Adaptation

The mechanisms of adaptation that allow the teleost Silurus glanis to maintain its resting oxygen consumption constant when the O2 partial pressure (PO2) m the inspired water (PIO2) varied between 40 and 3kPa were studied at 13 °C. Steadystate values of oxygen consumption, ventilatory and circulatory flow rates, PO2 in the inspired and expired water, PO2 and O2 concentration in the arterial and venous blood, haematocrit and acid--base status in the arterial blood were determined after 1-day exposures at selected PIO2 values. Whole-blood O2-binding characteristics were also determined. The key adaptation after 1 day of acclimation was maintenance of oxygen consumption by ventilatory adjustment with no change in blood flow rate or pH (no Bohr effect). At each PIO2 value (i) the ventilatory adjustment was minimal as the O2 extraction coefficient from water always remained around 80–90 % and (ii) PaO2 stayed constant at about 2kPa. Data are compared with previous results in crayfish and other teleosts. It is concluded that the principle of a constant O2 status in themilieu intérieur -- independent of large changes in PIO2 for a given state of activity -- should be valid in many crustaceans and teleosts.

Cardiovascular changes in the exercising emu

1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Content ◽  
Body Mass ◽  
Fold Increase ◽  
Exercise Heart Rate ◽  
Rate Of Oxygen Consumption ◽  
Cardiovascular Variables

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.

Effect of sympathetic blockade on diurnal variation of hemodynamic patterns

1989 ◽  
Vol 256 (3) ◽  
pp. R778-R785 ◽  
Author(s):  
M. I. Talan ◽  
B. T. Engel
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Base Line ◽  
Sympathetic Blockade ◽  
Selective Blockade ◽  
Arterial Blood

Heart rate, stroke volume, and intra-arterial blood pressure were monitored continuously in each of four monkeys, 18 consecutive h/day for several weeks. The mean heart rate, stroke volume, cardiac output, systolic and diastolic blood pressure, and total peripheral resistance were calculated for each minute and reduced to hourly means. After base-line data were collected for approximately 20 days, observation was continued for equal periods of time under conditions of alpha-sympathetic blockade, beta-sympathetic blockade, and double sympathetic blockade. This was achieved by intra-arterial infusion of prazosin, atenolol, or a combination of both in concentration sufficient for at least 75% reduction of response to injection of agonists. The results confirmed previous findings of a diurnal pattern characterized by a fall in cardiac output and a rise in total peripheral resistance throughout the night. This pattern was not eliminated by selective blockade, of alpha- or beta-sympathetic receptors or by double sympathetic blockade; in fact, it was exacerbated by sympathetic blockade, indicating that the sympathetic nervous system attenuates these events. Because these findings indicate that blood volume redistribution is probably not the mechanism mediating the observed effects, we have hypothesized that a diurnal loss in plasma volume may mediate the fall in cardiac output and that the rise in total peripheral resistance reflects a homeostatic regulation of arterial pressure.

Cardiopulmonary effects of continuous pressure breathing in hypothermic dogs

1965 ◽  
Vol 20 (4) ◽  
pp. 669-674 ◽  
Author(s):  
J. Salzano ◽  
F. G. Hall
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Negative Pressure ◽  
Alveolar Ventilation ◽  
Positive Pressure ◽  
Negative Pressure Breathing ◽  
Continuous Positive Pressure ◽  
Respiratory Dead Space

Continuous pressure breathing was studied in hypothermic anesthetized dogs. Alveolar ventilation decreased during continuous positive-pressure breathing and increased during continuous negative-pressure breathing. The changes in alveolar ventilation were due to changes in respiratory rate as well as in respiratory dead space. Cardiac output fell significantly during continuous positive-pressure breathing due to a reduction in heart rate and stroke volume. During continuous negative-pressure breathing cardiac output was only slightly greater than during control as a result of a fall in heart rate and an increase in stroke volume. Oxygen consumption was reduced to 60% of control during continuous positive-pressure breathing of 16 cm H2O but was 25% greater than control during continuous negative-pressure breathing. Qualitatively, CO2 production changed as did O2 consumption but was different quantitatively during continuous negative-pressure breathing indicating hyperventilation due to increased respiratory rate. Mean pulmonary artery pressures and pulmonary resistance varied directly with the applied intratracheal pressure. The results indicate that the hypothermic animal can tolerate an imposed stress such as continuous pressure breathing and can increase its oxygen consumption during continuous negative-pressure breathing as does the normothermic animal. hypothermia; respiratory dead space; metabolic rate; cardiac output Submitted on December 8, 1964

Constancy of stroke volume in ventricular responses to exertion

1959 ◽  
Vol 196 (4) ◽  
pp. 745-750 ◽  
Author(s):  
Robert F. Rushmer
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Cardiac Response ◽  
Indirect Measurements ◽  
Increase Stroke Volume ◽  
Normal Man ◽  
The Right ◽  
Response To Exercise ◽  
Indicator Dilution Techniques

Diastolic and systolic dimensions of the left ventricle and the free wall of the right ventricle in intact dogs are affected little by spontaneous exercise. The concept that stroke volume and heart rate in normal man increase by about the same relative amounts was derived from estimations of cardiac output, particularly in athletes, based upon indirect measurements using foreign gases or CO2. Data for man obtained with the modern cardiac catheterization or indicator dilution techniques confirm the impression derived from intact dogs that increased stroke volume is neither an essential nor a characteristic feature of the normal cardiac response to exercise. Stroke volume undoubtedly increases whenever cardiac output is increased with little change in heart rate (e.g. in athletes or in patients with chronic volume loads on the heart). Tachycardia produced experimentally with an artificial pacemaker in a resting dog causes a marked reduction in diastolic and systolic dimensions and in the stroke change of dimensions. The factors generally postulated to increase stroke volume during normal exercise may prevent the reduction in stroke volume accompanying tachycardia.

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