HLTH1004 W2 L2.3.5

Haemoglobin and Carbon Dioxide Transport

• Role of Haemoglobin

  • Present in red blood cells, haemoglobin primarily functions to transport oxygen, but it also carries carbon dioxide.

• Carbon Dioxide Production

  • Carbon dioxide is produced during cellular metabolism.

  • After production, carbon dioxide dissolves in plasma and diffuses into red blood cells.

• Formation of Carbonic Acid

  • Inside red blood cells, carbon dioxide is converted into carbonic acid.

Carbonic Acid and Its Dissonance

• Dissociation of Carbonic Acid

  • Carbonic acid dissociates into bicarbonate ions and hydrogen ions.

  • The bicarbonate ions diffuse into the plasma while exchanging with chloride ions (known as the chloride shift).

• Chloride Shift

  • This process involves the exchange of bicarbonate ions leaving the red blood cells in favor of chloride ions entering.

Hemoglobin Buffering Capacity

• Buffering by Hemoglobin

  • Hemoglobin molecules buffer hydrogen ions released during the dissociation of carbonic acid.

  • It is the only intracellular buffer system that has an immediate effect on the pH of extracellular fluid.

• Importance of Hemoglobin Buffering

  • Crucial for preventing significant changes in plasma pH during fluctuations of carbon dioxide levels.

  • Particularly significant during periods of increased metabolism, such as during exercise, when carbon dioxide production rises.