What is the Difference Between Bohr and Haldane Effect

The main difference between Bohr and Haldane effect is that Bohr effect is the decrease of the oxygen binding capacity of haemoglobin with the increase of the concentration of carbon dioxide or decrease in pH whereas Haldane effect is the decrease of the carbon dioxide binding capacity of haemoglobin with the rise in the concentration of oxygen. Furthermore, Bohr effect aids in the release of oxygen from oxyhemoglobin at the metabolizing tissues while Haldane effect aids in the release of carbon dioxide from carboxyhemoglobin in the lungs.

Bohr and Haldane’s effect are two properties of haemoglobin. They help the dissociation of respiratory gases from the haemoglobin molecule based on the physiological conditions of their final destination.

Key Areas Covered

1. What is Bohr Effect
     – Definition, Effect on Oxyhemoglobin, Importance
2. What is Haldane Effect
     – Definition, Effect on Carboxyhemoglobin, Importance
3. What are the Similarities Between Bohr and Haldane Effect
     – Outline of Common Features
4. What is the Difference Between Bohr and Haldane Effect
     – Comparison of Key Differences

Key Terms

Blood pH, Bohr Effect, Carboxyhemoglobin, Haldane Effect, Hemoglobin, Oxyhemoglobin

What is Bohr Effect

Bohr effect is a property of hemoglobin, aiding the release of oxygen at the metabolizing tissue. Metabolizing tissues produce carbon dioxide since they undergo cellular respiration. The blood takes up this carbon dioxide, increasing the pH of the blood. The increasing or the acidic pH results in the dissociation of oxyhemoglobin, releasing oxygen. Moreover, the Danish physiologist, Christian Bohrth described this phenomenon first  in 1904. He stated that the oxygen binding capacity of hemoglobin is inversely proportional to the acidity and the concentration of carbon dioxide.  

Figure 1: Hemoglobin

Bohr effect facilitates the release of oxygen from the blood at the metabolizing tissue. Generally, tissues require oxygen to undergo cellular respiration.

What is Haldane Effect

Haldane effect is another property of hemoglobin, aiding the release of carbon dioxide in the lungs. Lungs are the respiratory organs through which the respiratory gases exchange. The blood uptakes oxygen in the lungs to form oxyhemoglobin. And, this decreases the pH of the blood. Under the alkaline pH, carboxyhemoglobin dissociates to release carbon dioxide in the lungs.

Furthermore, the Scottish physiologist, John Scott Haldane first described this phenomenon. He described the effect of oxygen on the transport of carbon dioxide. The basis of the Haldane effect is the higher affinity of deoxygenated hemoglobin for carbon dioxide. In other words, the affinity of oxyhemoglobin for carbon dioxide is less than that of deoxygenated hemoglobin.

Figure 2: Oxygen Dissociation Curve

The main importance of the Haldane effect is that it increases the oxygen-binding capacity of blood with the release of carbon dioxide from the hemoglobin.

Similarities Between Bohr and Haldane Effect

• Bohr and Haldane effect are two properties of the hemoglobin molecule.
• They both involve in the release of oxygen and carbon dioxide at their final destinations.
• Also, both effects occur based on the physiological properties of the final destinations of these gases.

Difference Between Bohr and Haldane Effect

Definition

Bohr effect refers to the decrease in the oxygen affinity of a respiratory pigment such as hemoglobin in response to decreased blood pH resulting from increased carbon dioxide concentration in the blood. In contrast, Haldane effect refers to the decrease in the carbon dioxide affinity of hemoglobin in response to increased blood pH resulting from increased oxygen concentration in the blood. These definitions explain the main difference between Bohr and Haldane effect.

First Described by

Christian Bohr described the Bohr effect first while John Scott Haldane described the Haldane effect first.

Destination

Moreover, another difference between Bohr and Haldane effect is that the Bohr effect occurs at the metabolizing tissue while the Haldane effect occurs in the lungs.

Type of Respiratory Gas

Also, the type of respiratory gas is a major difference between Bohr and Haldane effect. Bohr effect describes the release of oxygen while the Haldane effect describes the release of carbon dioxide.

Physiological Conditions

Bohr effect is effective under low blood pH while Haldane effect is effective under high blood pH. Thus, this is one other difference between Bohr and Haldane effect.

Opposite Respiratory Gas

The take up of carbon dioxide at the metabolizing tissue leads to the Bohr effect while the uptake of oxygen in the lungs leads to the Haldane effect. 

Importance

Another difference between Bohr and Haldane effect is that Bohr effect facilitates the release of oxygen at the metabolizing tissue while the Haldane effect facilitates the binding of oxygen to the hemoglobin.

Conclusion

Bohr effect describes the release of oxygen at the metabolizing tissue. It occurs due to the low pH of the blood, emerged by the take up of carbon dioxide into the blood. On the other hand, Haldane effect describes the release of carbon dioxide in the lungs. It occurs due to the high pH of the blood, emerged by the take up of oxygen into the blood. Therefore, the main difference between Bohr and Haldane effect is the type of respiratory gas released from hemoglobin based on the blood pH.

Reference:

1. Patel AK, Cooper JS. Physiology, Bohr Effect. [Updated 2018 Sep 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan-. Available Here
2. Jakob SM, Kosonen P, Ruokonen E, Parviainen I, Takala J. The Haldane effect—an alternative explanation for increasing gastric mucosal PCO2 gradients? Br J Anaesth. 1999;83:740–746. doi: 10.1093/bja/83.5.740. Available Here

Image Courtesy:

1. “1904 Hemoglobin” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia   
2. “Oxyhaemoglobin dissociation curve” By Ratznium at English WikipediaLater versions were uploaded by Aaronsharpe at en.wikipedia. – Transferred from en.wikipedia to Commons. (Public Domain) via Commons Wikimedia  

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