Progressive Care Nursing Certification (PCCN) Practice Exam

What is the primary function of erythropoietin?

1. Stimulate kidney filtration

2. Signal bone marrow to produce red blood cells

3. Excrete nitrogenous waste

4. Regulate sodium and water balance

The correct answer is: Signal bone marrow to produce red blood cells

Erythropoietin is a hormone primarily produced by the kidneys in response to low levels of oxygen in the blood. Its main function is to signal the bone marrow to increase the production of red blood cells (RBCs). This increase in RBC production enhances the blood's capacity to transport oxygen, which is crucial during situations such as anemia or chronic hypoxia. When oxygen levels in the blood drop, erythropoietin is released into the bloodstream and acts directly on the erythroid progenitor cells in the bone marrow, prompting them to mature into red blood cells. This is a fundamental process for maintaining adequate oxygen delivery to tissues and organs, ensuring proper metabolic function. The other options relate to different physiological functions that are not associated with erythropoietin. For instance, stimulating kidney filtration, excreting nitrogenous waste, and regulating sodium and water balance are functions performed by the kidneys in various capacities, but they are not the primary role of erythropoietin. Understanding the specific role of erythropoietin is essential for recognizing its significance in hematology and clinical practices related to blood disorders.