Oxygen dissociation curve

Definition

Oxygen dissociation curve describes the relationship between the partial pressure of oxygen (pO2) and hemoglobin saturation. It is essential for understanding how oxygen is transported and released by red blood cells.

5 Must Know Facts For Your Next Test

1. The shape of the curve is sigmoidal (S-shaped) due to cooperative binding of oxygen to hemoglobin.
2. A rightward shift in the curve indicates decreased affinity of hemoglobin for oxygen, often caused by increased CO2, H+, temperature, or 2,3-BPG levels.
3. A leftward shift indicates increased affinity for oxygen, which can be caused by decreased CO2, H+, temperature, or 2,3-BPG levels.
4. At high pO2 levels (such as in the lungs), hemoglobin binds to oxygen more readily; at low pO2 levels (such as in tissues), it releases oxygen more easily.
5. The P50 value on the curve represents the partial pressure at which hemoglobin is 50% saturated with oxygen and serves as an indicator of hemoglobin's affinity for oxygen.

Review Questions

• What does a rightward shift in the oxygen dissociation curve signify?
• How does temperature affect the position of the oxygen dissociation curve?
• What does the P50 value indicate about hemoglobin's affinity for oxygen?

Related terms

Hemoglobin: A protein in red blood cells that binds to and transports oxygen throughout the body

Partial Pressure: The pressure contributed by a single type of gas in a mixture of gases

Bohr Effect: The physiological phenomenon where increased carbon dioxide concentration lowers blood pH and decreases hemoglobin's affinity for oxygen