Certified Transport Registered Nurse Certification Practice Exam

What physiological importance does the oxygen-hemoglobin dissociation curve serve?

1. It explains how oxygen is released to tissues

2. It measures lung compliance

3. It determines blood pH

4. It assesses airway resistance

The correct answer is: It explains how oxygen is released to tissues

The oxygen-hemoglobin dissociation curve is crucial for understanding how oxygen is transported in the blood and delivered to tissues. This curve illustrates the relationship between the partial pressure of oxygen (PaO2) and the saturation of hemoglobin with oxygen (SaO2). As oxygen binds to hemoglobin in the lungs, its affinity increases, allowing for efficient oxygen uptake. As the curve shifts to the right in the presence of certain factors (like increased carbon dioxide, lower pH, and higher temperature), hemoglobin releases oxygen more readily to the tissues that require it. This physiological mechanism is vital because it ensures that in various tissues where metabolic activity is high, oxygen is available where it is most needed. In contrast, the other options focus on different physiological processes that do not directly relate to the function of the oxygen-hemoglobin dissociation curve. For example, lung compliance pertains to the ability of the lungs to expand with pressure changes, blood pH measures acidity/basicity and does not directly affect the dissociation curve itself, and airway resistance relates to airflow dynamics in the respiratory system. Understanding the dissociation curve is essential for optimizing oxygen delivery in clinical settings, making it foundational knowledge for transport nurses.