Question
What would be a cause for the arrow shown in the graph:
A. Decrease in 2-3 DPG
B. Increase in body temperature.
C. Decrease in H+
D. Decrease in CO2
Show Answer
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Correct Answer » B Explanation |
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Ans: B. Increase in body temperature.
Right Shift is shown in the Oxygen Dissociation Curve.
Oxyhemoglobin dissociation curve
- It describes the relation between the partial pressure of oxygen (x-axis) and the oxygen saturation (y-axis).
- A hemoglobin molecule can bind up to four oxygen molecules in a reversible way.
- Hemoglobin’s affinity for oxygen increases as successive molecules of oxygen bind.
- More molecules bind as the oxygen partial pressure increases until the maximum amount that can be bound is reached. As this limit is approached, very little additional binding occurs and the curve levels out as the hemoglobin becomes saturated with oxygen. Hence the curve has a sigmoidal or S-shape.
- At pressures above about 60 mmHg, the standard dissociation curve is relatively flat, which means that the oxygen content of the blood does not change significantly even with large increases in the oxygen partial pressure.
- The partial pressure of oxygen in the blood at which the hemoglobin is 50% saturated, is known as the P50.
Righ shift :
- indicates that the hemoglobin has a decreased affinity for oxygen.
- This makes it more difficult for hemoglobin to bind to oxygen (requiring a higher partial pressure of oxygen to achieve the same oxygen saturation), but it makes it easier for the hemoglobin to release oxygen bound to it.
- The effect of this rightward shift of the curve increases the partial pressure of oxygen in the tissues when it is most needed, such as during exercise, or hemorrhagic shock.
- The right shift shows the decreased affinity, as would appear with an increase in either body temperature, hydrogen ions, 2,3-bisphosphoglycerate (2,3-BPG) concentration or carbon dioxide concentration.
Left Shift:
- indicates that the hemoglobin has an increased affinity for oxygen so that hemoglobin binds oxygen more easily, but unloads it more reluctantly.
- Left shift of the curve is a sign of hemoglobin’s increased affinity for oxygen (e.g. at the lungs).
