Which factor shifts the oxy-hemoglobin saturation curve to the right?

The oxy-hemoglobin saturation curve shifting to the right indicates a decreased affinity of hemoglobin for oxygen. This means that hemoglobin releases oxygen more readily to the tissues, which is crucial during times of increased metabolic demand.

One significant factor that can cause this shift is an increase in temperature. Elevated temperatures, often seen during exercise or fever, enhance the ability of hemoglobin to release oxygen due to changes in the hemoglobin structure and its interactions with oxygen molecules. This is known as the Bohr effect, where increased levels of carbon dioxide and lower pH are associated with higher temperatures, all promoting oxygen release.

When examining the other choices, they each have the opposite effect. Low carbon dioxide concentration and alkalosis would both shift the curve to the left, increasing hemoglobin's affinity for oxygen and making it less available to tissues. Additionally, a low concentration of 2,3 DPG, a molecule produced in red blood cells that enhances oxygen release, would also shift the curve to the left, further contributing to increased affinity for oxygen.

Thus, the increased temperature is the key factor that effectively shifts the oxy-hemoglobin saturation curve to the right, facilitating greater oxygen unloading where it is needed most.