Oxygen and carbon dioxide transport by haemoglobin
Haemoglobin is the iron-containing compound in blood that takes up oxygen and gives it off again. Henderson held that its iron makes it the carrier from lungs to tissues1. Haldane argued that breathing cannot be understood without knowing the conditions under which haemoglobin binds and releases oxygen5. The same blood also carries carbon dioxide, and the two gases influence each other7.
- Earliest held
- 1913, Henderson, L. J.
- Most discussed in
- Principles of General Physiology, 1915
- In the library
- 28 passages in 3 works
- Rewritten
- 2026-10-09
Iron and loose binding
Henderson, in The Fitness of the Environment (1913), attributed the power of haemoglobin to carry oxygen from the lungs to the tissues to the chemical behaviour of its iron. He added that copper plays a similar part in the haemocyanines of lower animals1. Bayliss, in Principles of General Physiology (1915), described two forms. Oxyhaemoglobin is regarded as a compound of reduced haemoglobin with oxygen. Exposure to a vacuum removes the oxygen and leaves haemoglobin, so the oxygen is said to be loosely combined2. Bayliss left the fuller chemistry of the pigment aside for the question at hand2.
Light and the spectrum
Bayliss also reported optical work on these compounds. Hartridge and Hill (1914) compared infra-red absorption by oxyhaemoglobin, reduced haemoglobin and the carbon monoxide compound. They found that carboxyhaemoglobin absorbs only about half as much as oxyhaemoglobin3. Bayliss noted that such measurements could estimate how much of each substance a solution holds3. He also recorded that Haldane and Lorrain Smith had shown light to change the equilibrium between oxygen, carbon monoxide and haemoglobin. From this he pointed toward a free energy calculation from the equilibrium constant4.
Curves outside the body
Haldane, in Organism and Environment as Illustrated by the Physiology of Breathing (1917), tied oxygen supply and breathing to the dissociation of oxyhaemoglobin5. The conditions of that dissociation can be studied outside the body, he wrote, if the conditions inside the body are reproduced. He said that failure to appreciate this had led to great error5. His Figure 1 plots a curve for blood with 40 mm. pressure of CO2 against a curve for blood within the body5.
Carbon dioxide uptake
Haldane gave figures for carbon dioxide. About 50 volumes of gas come from 100 volumes of human arterial blood under a vacuum, and venous blood holds only about 4 volumes more6. Christiansen, Douglas and Haldane found that blood takes up considerably more CO2 at a given pressure when the oxyhaemoglobin is dissociated7. Haldane read this as oxyhaemoglobin acting like a more acid substance than reduced haemoglobin8. The passages held here record no dispute over this reading.
haemoglobin contains iron, and the capacity of haemoglobin to unite with oxygen, and as oxyhaemoglobin to carry it from the lungs to the tissues is unquestion- ably due to the chemical behavior of that metal.
Henderson, L. J., 1913 · The Fitness of the Environment · open at passage 344This oxygen can be removed by exposure to a vacuum, so that it is stated to be " loosely combined," and haemoglobin remains.
Bayliss, W. M., 1915 · Principles of General Physiology · open at passage 2636the absorption of carboxyhsemoglobin is only about half that of oxyhaemoglobin
Bayliss, W. M., 1915 · Principles of General Physiology · open at passage 2690Light produces a change in the equilibrium between oxygen, carbon monoxide, and haemoglobin, as shown by Haldane and Lorrain Smith.
Bayliss, W. M., 1915 · Principles of General Physiology · open at passage 2690To understand the oxygen supply to the body, and the connection between oxygen supply and breathing, it is evidently necessary to understand the circumstances under which oxygen is taken up or given off by the haemoglobin of the blood.
Haldane, J. S., 1917 · Organism and Environment as Illustrated by the Physiology of Breathing · open at passage 60From 100 volumes of human arterial blood about 50 volumes of CO2 as gas are given off to a vacuum, and average venous blood contains only about 4 vol- umes more.
Haldane, J. S., 1917 · Organism and Environment as Illustrated by the Physiology of Breathing · open at passage 65We found that blood takes up considerably more CO2 at a given pressure of the gas when the oxy haemoglo- bin is dissociated than when it is present as oxyhaemo- globin.
Haldane, J. S., 1917 · Organism and Environment as Illustrated by the Physiology of Breathing · open at passage 65The oxyhaemoglobin thus acts as if it were a more acid substance than dissociated or reduced haemoglobin.
Haldane, J. S., 1917 · Organism and Environment as Illustrated by the Physiology of Breathing · open at passage 65
| 1915 | Principles of General Physiology · Bayliss, W. M. | 14 |
| 1917 | Organism and Environment as Illustrated by the Physiology of Breathing · Haldane, J. S. | 13 |
| 1913 | The Fitness of the Environment · Henderson, L. J. | 1 |