Blood and Carbon Dioxide - Essay Example

Haemoglobin, found in red blood cells, primarily transmits oxygen from the lungs to the tissues and CO2 from the tissues back to the lungs. Deoxyhemoglobin is a form of haemoglobin that has a higher affinity from CO2. CO2 to haemoglobin and forms a carbaminohemoglobin molecule. The process is reversible; thus, when it reaches the lungs, the CO2 dissociates freely from the haemoglobin and is expelled from the body. This mechanism accounts for about ten per cent of the CO2.

CO2 diffuses into red blood cells, where Carbonic anhydrase in the RBC quickly converts the CO2 into carbonic acid. This unstable molecule dissociates fast into bicarbonate ions and hydrogen ions, which bind to haemoglobin. The bicarbonate ions formed are transported out of the RBC into the blood liquid component in exchange for a chloride ion. Upon the blood reaching the lungs, the bicarbonate ion is transported back into the RBC in exchange for chloride ions. The hydrogen ions dissociate from the haemoglobin and bind to the bicarbonate ion, producing carbonic acid that, through the enzymatic action of CA, is converted back into CO2. The CO2 produced is expelled through exhalation by the lungs.