Relationship Between Haemoglobin and Partial Pressure of Oxygen
The partial pressure of oxygen or pO2 is the most important factor that determines the binding of oxygen with hemoglobin i.e. high pO2 higher the binding and low pO2 lowers the binding. When all the hemoglobins present completely binds with oxygen, the hemoglobin is said to be fully saturated whereas if there is free hemoglobin remaining then the hemoglobin is said to be partially saturated.
It means that the saturation level of hemoglobin with oxygen is expressed as its percent saturation. And this percent saturation is depicted by the oxygen-hemoglobin dissociation curve or oxygen dissociation curve.
Relationship Between Haemoglobin and Partial Pressure of Oxygen
This curve is a sigmoid-shaped curve with the following characteristics:
- The partial pressure of oxygen determines the saturation of hemoglobin i.e. high pO2 high Hb-O2 binding and 100% saturation, whereas low pO2 low Hb-O2 binding, and partial saturation.
- In resting condition i.e. at around pO2 of 40 mmHg the Hb is 75% saturated. It means that when a person is at rest only 25% of the available O2 is unloaded into the tissues.
- At around 60 to 100 mmHg pO2 the blood takes an almost full load of oxygen i.e. it gets saturated up to 90%. This is the reason why at higher altitudes people can perform well.
- In 20 mmHg Hb saturation drops at around 35% O2. That means between 40 mmHg to 20 mmHg Hb saturation drops from 75% to 35% due to large quantity dumping of oxygen. This is seen in active tissues as they require large quantities of oxygen.
- Each 100 mL of oxygenated blood provides 5 mL of gaseous O2 to the tissues.
Oxygen Transport in Blood
Oxygen is transported in the blood by binding to hemoglobin. Blood is responsible for the transportation of gases between the lungs and body tissues. Oxygen is transported bound to hemoglobin as it does not dissolve well in water present in plasma i.e. 97% of oxygen is transported with hemoglobin and the remaining 3% in plasma.
In this article, we will cover how oxygen is transported in blood, in detail.
Table of Content
- How is Oxygen Transported in Human Beings?
- Haemoglobin Protein in Blood
- Relationship Between Haemoglobin and Partial Pressure of Oxygen
- Factors Affecting Affinity of Haemoglobin for Oxygen
- Conclusion – Transport of Oxygen in Blood
- FAQs on How is Oxygen Transported in Human Beings?