Internal Respiration:
- The exchange of gases that takes place between blood and the tissue cells. Opposite of what lung does.
- Oxygen is un-loaded and carbon dioxide is loaded into the blood.
- CO2 diffusing out of tissue cells enters blood. It then combines with H2O to form Carbonic Acid. This quickly releases the bicarbonate ions.
- Most conversions of CO2 to bicarbonate ions actually occurs inside RBCs, where a special enzyme is available to speed up the reaction.
- Then the bicarbonate ions diffuse out into plasma.
- At the same time, oxygen is released form hemoglobin. Oxygen diffuses quickly out of blood and into tissue cells.