Neonatal Nurse Practitioner Practice Exam

In which physiological condition does hemoglobin more easily release oxygen to the tissues?

1. Alkalosis

2. Acidosis

3. Hypothermia

4. Hypercapnia

The correct answer is: Acidosis

The correct answer is acidosis, as this physiological condition promotes the release of oxygen from hemoglobin to the tissues, a phenomenon known as the Bohr effect. In acidic environments, there is an increase in hydrogen ions (H+), which causes hemoglobin to undergo a conformational change, decreasing its affinity for oxygen. This facilitates the unloading of oxygen where it is most needed, such as in metabolically active tissues that often produce excess carbon dioxide and lactic acid, leading to a lower pH. In states of alkalosis, the pH is elevated, which increases hemoglobin's affinity for oxygen, making it more difficult for hemoglobin to release oxygen to the tissues. Hypothermia lowers metabolic rates and shifts the oxygen-hemoglobin dissociation curve to the left, further enhancing hemoglobin's affinity for oxygen. Hypercapnia, which involves elevated carbon dioxide levels, can enhance oxygen release to some degree through increased acidity, but its overall effect is not as pronounced as acidosis. Hence, acidosis is the primary condition under which hemoglobin releases oxygen more readily to the tissues.