Question

Discuss ways in which carbon dioxide is transported

Answer 1

There are three means by which carbon dioxide is transported in the bloodstream from peripheral tissues and back to the lungs: 

1.  dissolved gas, 
2. bicarbonate, and 
3.  carbaminohemoglobin bound to hemoglobin (and other proteins).

As carbon dioxide diffuses into the bloodstream from peripheral tissues, approximately 10% of it remains dissolved either in plasma or the blood's extracellular fluid matrix, to a partial pressure of about 45 mmHg.[2] Most of the carbon dioxide diffusing through the capillaries and ultimately into the red blood cells combines with water via a chemical reaction catalyzed by the enzyme carbonic anhydrase catalyzes, forming carbonic acid. Carbonic acid almost immediately dissociates into a bicarbonate anion (HCO₃^-) and a proton. Thus, bicarbonate is the primary means by which carbon dioxide is transport occurs throughout the bloodstream according to the equation
CO₂ + H₂O --> H₂CO₃ --> H⁺ + HCO₃^-.