Curve oxyhemoglobin dissociation

Describe the physiological significance of the steep and plateau portions of the oxyhemoglobin dissociation curve... 

The P02 of blood is the major factor determining the amount of oxygen chemically combined with hemoglobin, or the percent of hemoglobin saturation. The relationship between these two variables is illustrated graphically by the oxyhemoglobin dissociation curve (see Figure 17.6). This relationship is not... 

In the case where the blood flow is laminar, as within hollow-fiber oxygenators, the rates of blood oxygenation can be predicted on a theoretical basis. Due to the shape of the oxyhemoglobin dissociation curve and the fact that the oxygen partial... 

FIGURE 20.2. Effect of carboxyhemoglobin (COHb) upon the shape of the oxyhemoglobin dissociation curve in healthy males. Based on data of Haldane and Priestley (1935) as presented by Shephard (1983). 

There are many other events that can produce a significant reduction in the RBC mass and a subsequent decrease in the oxygen-carrying capacity of the blood. Normally, the blood volume is maintained at a relatively constant level hence, any process or event that causes a reduction in either RBCs or hemoglobin produces a condition known as an anemia. Anemias can also shift the oxyhemoglobin dissociation curve... 

Figure 2 Oxyhemoglobin dissociation curve. Modifiers of oxygen affinity - increase in plasma pH, decrease in temperature, decrease in 2,3-BPG. Modifiers of oxygen unloading -decrease in plasma pH, increase in temperature, increase in 2,3-BPG.

As mentioned previously, CO competes with 02 for binding of hemoglobin, but, in addition, it also binds other proteins such as myoglobin, cytochrome c oxidase, and cytochrome P-450. Carbon monoxide also impairs the facilitated diffusion of 02 to the mitochondria, shifting the oxyhemoglobin dissociation curve to the left. Alteration of oxyhemoglobin dissociation curve by COHb occurs in such a manner that 02 is released to tissues with great difficulty and at a lower 02 tension. 

While this concept for the control of erythropoiesis is generally accepted, there are at present insufficient data to determine quantitative relationships among the variables involved. In addition, some auxiliary systems must be included to describe fully the erythropoietic response to stress such as hypoxia. The performance of the respiratory system and the relationships expressed by the oxyhemoglobin dissociation curve affect the oxygenation state of the blood. Blood volume, and in particular plasma volume, affect hemoglobin concentration which limits the amount... 

Oxyhemoglobin dissociation curve The equilibrium relationship between hemoglobin saturation and... 

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