Oxygen Tension Distribution in Water and Blood at the Secondary Lamella of the Dogfish Gill

1971 ◽  
Vol 55 (2) ◽  
pp. 399-408
Author(s):  
G. M. HUGHES ◽  
B. A. HILLS
Keyword(s):  
Oxygen Tension ◽  
Oxygen Dissociation Curve ◽  
Dissociation Curve ◽  
Tension Distribution ◽  
Oxygen Dissociation ◽  
Before And After ◽  
Secondary Lamella ◽  
Oxygen Tensions ◽  
Counter Current

1. An analysis is given which makes it possible to trace out the changes in oxygen tensions in the blood and water during their passage along a secondary lamella of the dogfish gill. 2. The analysis depends on a knowledge of the oxygen-dissociation curve of the blood, the shape of the secondary lamella and the oxygen tensions of the two media before and after their passage through the gills. It indicates the differences to be expected according to whether the flows are co-current or counter-current. 3. The method, with modifications, could be applied to the gills of all fishes.

Distribution of Oxygen Tension in the Blood and Water Along the Secondary Lamella of the Icefish Gill

1972 ◽  
Vol 56 (2) ◽  
pp. 481-492
Author(s):  
G. M. HUGHES
Keyword(s):  
Current Flow ◽  
Dissociation Curve ◽  
Exchange Area ◽  
Gill Area ◽  
Secondary Lamella ◽  
Oxygen Tensions ◽  
Counter Current ◽  
O2 Dissociation Curve ◽  
Very High ◽  
O2 Transfer

1. Measurements of the gill area of two specimens of Chaenocephalus aceratus indicate that the resistance to water flow and overall exchange area are even less than had been supposed from work with other icefish. 2. Measurements of the oxygen tensions in the water and in blood entering and leaving the gills are used to determine the expected distribution of O2 tensions along a typical secondary lamella profile. The advantage of counter-current over co-current flow is clearly indicated by such analyses. 3. The absence of complications due to the O2 dissociation curve of the blood facilitates an extension of the analysis to different theoretical secondary lamellar profiles. It is shown that profiles similar to those usually found in fish gills are more efficient in maintaining O2 transfer. 4. Although the percentage utilization of O2 in the water passing through the gills is relatively low, the effectiveness of oxygenating the blood is very high in the icefish gill.

Gas Exchange and its Effect on Blood Gas Concentrations in the Amphibian, Xenopus Laevis

1974 ◽  
Vol 60 (2) ◽  
pp. 567-579
Author(s):  
M. G. EMILIO ◽  
G. SHELTON
Keyword(s):  
Body Volume ◽  
Oxygen Dissociation Curve ◽  
Blood Gas ◽  
Limited Extent ◽  
Dissociation Curve ◽  
Blood Flows ◽  
Normal Breathing ◽  
Oxygen Dissociation ◽  
Oxygen Stores ◽  
Oxygen Tensions

1. Unrestrained Xenopus with access to air had an oxygen consumption, as measured at 20 °C by manometric and electrode techniques, of approximately 4.5 ml O2 100 g-1 h-1 of which 1.1 ml was taken in through the skin. 2. Measurements of body volume showed that the rate of oxygen uptake from the lungs was high when the animal was at the surface but fell rapidly during the first few minutes of a dive. 3. Oxygen tensions in systemic (80 mmHg) and pulmocutaneous (60 mmHg) vessels provided evidence for separation of blood flows in the ventricle of the animal when breathing air. The tensions fell in all parts of the circulation throughout a dive. 4. The above data, together with a conventionally determined oxygen dissociation curve, show that both blood and lungs are used to a limited extent as oxygen stores during a dive, the blood being more important. The stores do not permit tissue consumption to go on at a uniform rate throughout a normal breathing-diving cycle.

Red-cell 2,3-diphosphoglycerate in patients with hyperthyroidism

1980 ◽  
Vol 93 (4) ◽  
pp. 424-429 ◽  
Author(s):  
J. L. Alvarez-Sala ◽  
M. A. Urbán ◽  
J. J. Sicilia ◽  
A. J. Diaz Fdez ◽  
F. Fdez Mendieta ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Control Group ◽  
Red Cell ◽  
Oxygen Dissociation Curve ◽  
Dissociation Curve ◽  
Oxygen Dissociation ◽  
The Right ◽  
Serum Thyroid Hormones ◽  
Hyperthyroid Patients ◽  
2,3 Dpg

Abstract. In 21 hyperthyroid female patients studied on 29 occasions, high levels of red-cell 2,3-diphosphoglycerate (2,3-DPG) have been found (5.75 ± 0.7 mm) which, compared to a euthyroid control group (4.88 ± 0.4 mm), could not be accounted for by differences in haematocrit, haemoglobin or phosphataemia. A significant correlation was found (P < 0.05) between serum thyroid hormones and the 2,3-DPG concentration in the hyperthyroid patients. Eight of these patients were reexamined after treatment and normalization of thyroid function, showed a regression to normal 2,3-DPG values (4.81 ± 0.6 mm) which could not be attributed to variations in haematocrit, haemoglobin or phosphataemia either. We therefore deduce that the shift to the right in the haemoglobin oxygen dissociation curve observed in patients of this type may be due to an increase in the red-cell 2,3-DPG content.

scholarly journals Hemoglobin Non-equilibrium Oxygen Dissociation Curve

2020 ◽  
Author(s):  
Rosella Scrima ◽  
Sabino Fugetto ◽  
Nazzareno Capitanio ◽  
Domenico L. Gatti
Keyword(s):  
Partial Pressure ◽  
Correct Diagnosis ◽  
Oxygen Affinity ◽  
Oxygen Dissociation Curve ◽  
Dissociation Curve ◽  
High Affinity ◽  
Oxygen Dissociation ◽  
Sequential Binding ◽  
Non Equilibrium

AbstractAbnormal hemoglobins can have major consequences for tissue delivery of oxygen. Correct diagnosis of hemoglobinopathies with altered oxygen affinity requires a determination of hemoglobin oxygen dissociation curve (ODC), which relates the hemoglobin oxygen saturation to the partial pressure of oxygen in the blood. Determination of the ODC of human hemoglobin is typically carried out under conditions in which hemoglobin is in equilibrium with O2 at each partial pressure. However, in the human body due to the fast transit of RBCs through tissues hemoglobin oxygen exchanges occur under non-equilibrium conditions. We describe the determination of non-equilibrium ODC, and show that under these conditions Hb cooperativity has two apparent components in the Adair, Perutz, and MWC models of Hb. The first component, which we call sequential cooperativity, accounts for ∼70% of Hb cooperativity, and emerges from the constraint of sequential binding that is shared by the three models. The second component, which we call conformational cooperativity, accounts for ∼30% of Hb cooperativity, and is due either to a conformational equilibrium between low affinity and high affinity tetramers (as in the MWC model), or to a conformational change from low to high affinity once two of the tetramer sites are occupied (Perutz model).

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