The percentage of hemoglobin saturated with oxygen will increase when which of the following occurs?
**Core Concept**
The percentage of hemoglobin saturated with oxygen is determined by the partial pressure of oxygen (pO2) in the blood, the affinity of hemoglobin for oxygen, and the pH of the blood. This concept is crucial in understanding oxygen delivery to tissues and is essential for medical professionals to assess and manage various clinical conditions.
**Why the Correct Answer is Right**
The Bohr effect describes how a decrease in pH (increase in acidity) of the blood decreases the affinity of hemoglobin for oxygen, resulting in an increase in the percentage of hemoglobin saturated with oxygen. This is because the deprotonation of hemoglobin's histidine residues increases the oxygen affinity of the protein, allowing more oxygen to be released to tissues. In conditions of respiratory acidosis or lactic acidosis, the pH of the blood decreases, leading to an increase in the percentage of hemoglobin saturated with oxygen.
**Why Each Wrong Option is Incorrect**
**Option A:** An increase in pCO2 would lead to a decrease in pH, but this is not the primary factor in determining the percentage of hemoglobin saturated with oxygen.
**Option B:** An increase in temperature would actually decrease the affinity of hemoglobin for oxygen, leading to a decrease in the percentage of hemoglobin saturated with oxygen.
**Option C:** An increase in 2,3-bisphosphoglycerate (2,3-BPG) would actually decrease the affinity of hemoglobin for oxygen, leading to a decrease in the percentage of hemoglobin saturated with oxygen.
**Clinical Pearl / High-Yield Fact**
The Bohr effect is a crucial concept in understanding the regulation of oxygen delivery to tissues and is essential for medical professionals to assess and manage conditions such as respiratory acidosis, lactic acidosis, and anemia.
**Correct Answer:** C.