Respiratory Function in the South American Lungfish, Lepidosiren Paradoxa (Fitz)

1967 ◽  
Vol 46 (2) ◽  
pp. 205-218
Author(s):  
KJELL JOHANSEN ◽  
CLAUDE LENFANT
Keyword(s):  
Gas Exchange ◽  
Venous Blood ◽  
South American ◽  
O2 Uptake ◽  
The South ◽  
Mechanical Agitation ◽  
Air Breathing ◽  
Arterial Blood ◽  
Dissociation Curves ◽  
Branchial Arteries

1. Respiratory properties of blood and pattern of branchial and pulmonary gas exchange have been studied in twelve specimens of the South American lungfish, Lepidosiren paradoxa (Fitz). 2. Haematocrit ranged from 14 to 19% and blood oxygen capacity from 4.9 to 6.8 vol. %. The blood had a high affinity for O2 with a P50 value of 10.5 mm. Hg at Pco2 6 mm. Hg and temperature 23° C. The Bohr effect was low. 3. The CO2 dissociation curves show a steep ascending slope resulting in a relatively high CO2 combining power at physiological values of blood Pco2 The Haldane effect was small. Buffering capacity of oxygenated whole blood was high and exceeded that in typical water breathers. 4. Air breathing was prominent and intervals between air breaths varied from 3 to 10 min. Branchial respiratory movements were extremely shallow and showed a labile frequency. Air breathing was stimulated by hypoxic and hypercarbic water while hyperoxygenated water had no effect. Branchial respiratory rate showed a marked acceleration in response to mechanical agitation of the water. 5. Gas exchange was predominantly carried out by pulmonary breathing. In less than 10 min. the PO2 of expired gas dropped from 150 mm. Hg to less than 30 mm. Hg. The shallow branchial breathing with very low ventilation values resulted in a low O2 uptake via the gills. 6. Blood-gas analysis documented a clear selective passage of blood through the only partially divided heart. A consistently higher PO2 in dorsal aortic than in pulmonary arterial blood indicates a preferential passage of pulmonary venous blood to the anterior branchial arteries giving rise to most of the systemic circulation while systemic venous blood was largely conveyed to the most posterior branchial arteries giving rise to the pulmonary arteries. 7. The oxygen uptake for fish resting in water with access to air averaged 53.4 ml./hr./kg. Exposure to air lowered the O2 uptake markedly. 8. The increased importance of pulmonary breathing in Lepidosiren is discussed in relation to the transition from water breathing to air breathing.

Gas exchange and its control in non-steady-state systems: the consequences of evolution from water to air breathing in the vertebrates

1988 ◽  
Vol 66 (1) ◽  
pp. 109-123 ◽  
Author(s):  
G. Shelton ◽  
P. C. Croghan
Keyword(s):  
Steady State ◽  
Gas Exchange ◽  
Dynamic Models ◽  
Continuous Process ◽  
Circulatory System ◽  
Lung Ventilation ◽  
Burst Duration ◽  
Air Breathing ◽  
Arterial Blood ◽  
Dissociation Curves

Control of breathing and gas exchange has been extensively investigated in unimodal animals, particularly mammals, in which ventilation is characteristically a regular and continuous process and gas exchange approximates to a steady-state system. Both static and dynamic models have been developed in control-theory analyses. Similar analyses are possible in unimodal fish, though few have been carried out. Control in bimodal animals, such as air-breathing fish and amphibians, is more difficult to understand and model. The evolutionary change from water to air breathing in vertebrates involves not only the adjustment of many control processes but also the development, in the early stages, of non steady states in gas exchangers, blood, and tissues. A simple control-system model, differing from mammalian counterparts in its greater emphasis on storage functions and its intermittently activated controller, is described for two suggested stages in the evolution of air breathing. The first of these stages is air gulping, in which a fixed and rather brief pattern of air breathing is activated by internal signals generated as a result of the inadequacy of the gills to provide sufficient oxygen for tissue metabolism. The second stage is that of burst breathing, in which lung ventilation is both begun and ended by internal signals so that burst duration is variable. The effects of adjusting parameters on variables of evolutionary importance, such as dive duration, burst duration, store renewal, and metabolic rate, can be examined in these two versions of the model. Refinements to incorporate arterial and venous compartments in the circulatory system, the shunting of venous and arterial blood streams in the heart, realistic oxygen dissociation curves, controller inputs from a wider range of sources, and the capacity to respond to some conditions with changes in ventilation rate as well as in burst and dive durations, are being developed. They should make the complex, non-steady-state interactions between gas exchangers, circulating blood, and tissues easier to understand and indicate the likely steps toward the evolution of steady-state systems seen in birds and mammals.

Blood Gases of the South American Lungfish, Lepidosiren paradoxa: A Comparison to Other Air-breathing Fish and to Amphibians

2016 ◽  
pp. 243-254
Author(s):  
Jalile Amin-Naves ◽  
A.P. Sanchez ◽  
M. Bassi ◽  
H. Giusti ◽  
F.T. Rantin ◽  
...  
Keyword(s):  
Blood Gases ◽  
South American ◽  
The South ◽  
Air Breathing

scholarly journals Effects of aerial hypoxia and temperature on pulmonary breathing pattern and gas exchange in the South American lungfish, Lepidosiren paradoxa

2017 ◽  
Vol 207 ◽  
pp. 107-115 ◽  
Author(s):  
Glauber S.F. da Silva ◽  
Daniela A.D.N. Ventura ◽  
Lucas A. Zena ◽  
Humberto Giusti ◽  
Mogens L. Glass ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Breathing Pattern ◽  
South American ◽  
The South

Oxygen uptake in air and water in the air-breathing reedfish Calamoichthys calabaricus: role of skin, gills and lungs

1982 ◽  
Vol 97 (1) ◽  
pp. 179-186
Author(s):  
R. Sacca ◽  
W. Burggren
Keyword(s):  
Gas Exchange ◽  
Oxygen Uptake ◽  
Natural Environment ◽  
Average Duration ◽  
O2 Uptake ◽  
Total Oxygen ◽  
Air Exposure ◽  
Air Breathing

The reedfish Calamoichthys calabaricus (Smith) is amphibious, making voluntary excursions on to land (in a simulated natural environment) an average of 6 +/− 4 times/day for an average duration of 2.3 +/− 1.3 min. Oxygen uptake is achieved by the gills, skin and large, paired lungs. In water at 27 degrees C, total oxygen uptake is 0.088 ml O2/g.h. The lungs account for 40%, the gills 28%, and the skin 32% of total VO2. Total oxygen uptake during 2 h of air exposure increases from 0.117 ml O2/g.h to 0.286 ml O2/g.h, due largely to an enhanced lung VO2 and a small increase in skin VO2. Calamoichthys is both capable of aerial gas exchange and adapted to maintain O2 uptake during brief terrestrial excursions.

Oxygen respiratory gas analysis by sine-wave measurement: a theoretical model

1996 ◽  
Vol 81 (2) ◽  
pp. 985-997 ◽  
Author(s):  
C. E. Hahn
Keyword(s):  
Gas Exchange ◽  
Dead Space ◽  
Venous Blood ◽  
Sine Wave ◽  
Inert Gas ◽  
Mixed Venous Blood ◽  
Arterial Blood ◽  
Partial Pressures ◽  
The Mean ◽  
Mixed Venous

A sinusoidal forcing function inert-gas-exchange model (C. E. W. Hahn, A. M. S. Black, S. A. Barton, and I. Scott. J. Appl. Physiol. 75: 1863–1876, 1993) is modified by replacing the inspired inert gas with oxygen, which then behaves mathematically in the gas phase as if it were an inert gas. A simple perturbation theory is developed that relates the ratios of the amplitudes of the inspired, end-expired, and mixed-expired oxygen sine-wave oscillations to the airways' dead space volume and lung alveolar volume. These relationships are independent of oxygen consumption, the gas-exchange ratio, and the mean fractional inspired (FIO2) and expired oxygen partial pressures. The model also predicts that blood flow shunt fraction (Qs/QT) is directly related to the oxygen sine-wave amplitude perturbations transmitted to end-expired air and arterial and mixed-venous blood through two simple equations. When the mean FIO2 is sufficiently high for arterial hemoglobin to be fully saturated, oxygen behaves mathematically in the blood like a low-solubility inert gas, and the amplitudes of the arterial and end-expired sine-wave perturbations are directly related to Qs/QT. This relationship is independent of the mean arterial and mixed-venous oxygen partial pressures and is also free from mixed-venous perturbation effects at high forcing frequencies. When arterial blood is not fully saturated, the theory predicts that QS/QT is directly related to the ratio of the amplitudes of the induced-saturation sinusoids in arterial and mixed-venous blood. The model therefore predicts that 1) on-line calculation of airway dead space and end-expired lung volume can be made by the addition of an oxygen sine-wave perturbation component to the mean FIO2; and (2) QS/QT can be measured from the resultant oxygen perturbation sine-wave amplitudes in the expired gas and in arterial and mixed-venous blood and is independent of the mean blood oxygen partial pressure and oxyhemoglobin saturation values. These calculations can be updated at the sine-wave forcing period, typically 2–4 min.

scholarly journals Regional variability in diving physiology and behavior in a widely distributed air-breathing marine predator, the South American sea lion (Otaria byronia)

2016 ◽  
Vol 219 (15) ◽  
pp. 2320-2330 ◽  
Author(s):  
Luis A. Hückstädt ◽  
Michael S. Tift ◽  
Federico Riet-Sapriza ◽  
Valentina Franco-Trecu ◽  
Alastair M. M. Baylis ◽  
...  
Keyword(s):  
South American ◽  
The South ◽  
Sea Lion ◽  
Regional Variability ◽  
Diving Physiology ◽  
Air Breathing ◽  
Marine Predator ◽  
South American Sea Lion ◽  
And Behavior

Mechanism of pulmonary gas exchange and CO2 transport during breath holding

1959 ◽  
Vol 14 (5) ◽  
pp. 706-710 ◽  
Author(s):  
John C. Mithoefer
Keyword(s):  
Gas Exchange ◽  
Lung Volume ◽  
Venous Blood ◽  
Volume Shrinkage ◽  
Breath Holding ◽  
Mixed Venous Blood ◽  
Co2 Transport ◽  
Arterial Blood ◽  
Mixed Venous ◽  
Haldane Effect

Experiments describe the changes in PaCOCO2 and lung volume shrinkage during breath holding with O2 in man and the PaCOCO2, pH and CO2 content of arterial and mixed venous blood during breath holding in the dog. An explanation is offered for the aberrations in CO2 transport and exchange which occur during apnea. A self-perpetuating cycle is established during breath holding which is initiated by the arrest of the ventilatory output of Co2. The arterial PaCOCo2 rises rapidly as a result of decreased clearance of Co2 from venous blood, the concentrating effect of lung volume shrinkage and the Haldane effect from oxygenation of hemoglobin. The venous PaCOCO2 rises more slowly because of the uptake of Co2 by the tissues and the Haldane effect from reduction of oxyhemoglobin. By this mechanism the Co2 output into the lungs progressively falls and eventually stops. The cycle then is reversed and Co2 moves from lungs to arterial blood. Submitted on March 2, 1959

scholarly journals Acute effects of temperature and hypercarbia on cutaneous and branchial gas exchange in the South American lungfish, Lepidosiren paradoxa

2017 ◽  
Vol 63 ◽  
pp. 112-118 ◽  
Author(s):  
Lucas A. Zena ◽  
Kênia C. Bícego ◽  
Glauber S.F. da Silva ◽  
Humberto Giusti ◽  
Mogens L. Glass ◽  
...  
Keyword(s):  
Gas Exchange ◽  
South American ◽  
Acute Effects ◽  
The South ◽  
Effects Of Temperature

Gas Exchange and Transport During Intermittent Breathing in Chelonian Reptiles

1979 ◽  
Vol 82 (1) ◽  
pp. 75-92 ◽  
Author(s):  
WARREN W. BURGGREN ◽  
GRAHAM SHELTON
Keyword(s):  
Gas Exchange ◽  
Venous Blood ◽  
Lung Ventilation ◽  
Gas Composition ◽  
Blood Gas ◽  
Carbon Dioxide Gas ◽  
Arterial Blood ◽  
Limited Function ◽  
Pulmonary Arterial ◽  
Arteries And Veins

1. The oxygen and carbon dioxide gas tensions in lung gas and blood from the central and peripheral arteries and veins have been measured in unrestrained, undisturbed turtles (Pseudemys scripta) and tortoises (Testudo graecd). 2. Lung and blood gas composition fluctuates widely with intermittent and irregular lung ventilation. The pulmonary gas exchange ratio, which progressively falls during apnoea to as low as 0.2-0.3 in Pseudemys, rises dramatically to over 1.5 during lung ventilation in both species. It is postulated that CO2, which has been passively stored by entering the tissues along gas tension gradients during apnoea, becomes rapidly eliminated into the lungs during ventilation. In diving Pseudemys the lung has only a limited function as a CO2 sink compared to the tissues, but the lung acts as a large oxygen store, which can be drawn upon during apnoea through periodic increases in lung perfusion. 3. Blood gas tensions in the various systemic arches reflect the proximity of the arch's origin to the systemic or pulmonary venous blood streams in the ventricle. Thus, the brachiocephalic artery and right aorta have identical blood gas compositions while the composition of the left aorta is intermediate between these and that in the pulmonary. These relationships are unaffected by normal intermittent breathing. However, this does affect both the origin and composition of systemic and pulmonary arterial blood, such that the greatest proportion of oxygenated blood perfuses the systemic vascular bed during lung ventilation, while the greatest proportion of deoxygenated blood perfuses the lungs during apnoea. 4. These data are discussed in the light of the marked cardiovascular adjustments to intermittent breathing, which occur in chelonian reptiles.

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