Blood : a study in general physiology / by Lawrence J. Henderson.

  • Lawrence Joseph Henderson
Date:
1928
Catalogue details

Licence: In copyright

Credit: Blood : a study in general physiology / by Lawrence J. Henderson. Source: Wellcome Collection.

    106/434 page 80
    3, 20, 40, and 80 mm. respectively. These curves are all similar, and all roughly approximate to curves of Hill’s equation, [Hb] [Hb02] The values of h are, however, different from curve to curve and h is approximately a linear function of carbon dioxide pressure: k = a-pC02 + b. Therefore the facts represented by the family of oxygen dissociation curves may also be represented by an equa¬ tion of the form, «.pC01 + & = J^.p0,“. This is, indeed, a rough approximation. But it will serve, since it includes all the relevant variables for the case of a single specimen of blood. Needless to say, it would be possible to fit the curves with an equation as closely as experimental precision permits, but this is unnecessary for the present consideration. At this point two conclusions may be deduced. First, the capacity for oxygen of a given sample of blood at a given pressure of oxygen is constant only when the pres¬ sure of carbon dioxide is also constant. Secondly, the fall in concentration of carbon dioxide in the lung is accom¬ panied by a rise in the capacity of the blood to absorb oxygen, and the rise in concentration of carbonic acid in the tissues is accompanied by a fall in the capacity to ab¬ sorb oxygen. Therefore the physiological process of oxy¬ gen transport is not represented by a single member of the family of oxygen dissociation curves of figure 13, but by a different curve, or rather cycle, which cuts across these curves. The cycle is shown on figure 13. To those who have not themselves experienced that state of bewilderment which is the usual condition of the
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