list and explain the three ways in which carbon dioxide is transported by blood in human body support your answer with suitable diagram
Carbon dioxide molecules are transported in the blood from body tissues to the lungs by one of three methods:
1. dissolution directly into the blood,
2. binding to haemoglobin,
3. carried as a bicarbonate ion.
1. Carbon dioxide is more soluble in blood than oxygen. About 5 to 7 percent of all carbon dioxide is dissolved in the plasma.
2. Carbon dioxide can bind to plasma proteins or can enter red blood cells and bind to hemoglobin. About 10 per cent of it is transported in this form. When carbon dioxide binds to hemoglobin, a molecule called carbaminohemoglobin is formed.
3. Majority of carbon dioxide molecules (85%) are carried as part of the bicarbonate buffer system. In this, carbon dioxide diffuses into the red blood cells. Carbonic anhydrase within the red blood cells quickly converts the carbon dioxide into carbonic acid (H2CO3).
H+ ions bind to haemoglobin. When blood reached lungs, H+ ion dissociates from the haemoglobin and binds to the bicarbonate ion. This produces the carbonic acid intermediate, which is converted back into carbon dioxide. The carbon dioxide produced is expelled through the lungs.
Diagram for transportation of Carbon dioxide by blood.
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