An increase in pCO2 will cause increased dissociation of oxygen from hemoglobin, and this phenomenon occurs in the systemic tissues.
When pCO2 levels rise, such as during periods of increased cellular metabolism in the tissues, hemoglobin’s affinity for oxygen decreases. This is due to a physiological process known as the Bohr effect, where elevated levels of carbon dioxide and lower pH (which accompanies increased pCO2) promote the release of oxygen from hemoglobin. This is crucial because tissues that are metabolically active produce more CO2, and thus benefit from the enhanced oxygen delivery as hemoglobin releases more of it.
In contrast, in the lungs, where CO2 is being expelled and pCO2 levels are lower, hemoglobin’s affinity for oxygen increases, facilitating oxygen uptake. Therefore, the dissociation of oxygen from hemoglobin is heightened in systemic tissues rather than in the lungs in response to increased pCO2.