What is one major function of the kidneys beyond filtering blood?

One major function of the kidneys, beyond their primary role in filtering blood and removing waste products, is the production of hormones. The kidneys play a significant role in maintaining homeostasis and regulating various physiological processes through the secretion of hormones such as erythropoietin (EPO) and renin.

Erythropoietin is crucial for the production of red blood cells in the bone marrow, enhancing oxygen delivery to tissues. Renin is involved in the regulation of blood pressure and fluid balance by influencing the renin-angiotensin-aldosterone system, which helps control blood volume and systemic vascular resistance.

This hormone production is essential for maintaining overall bodily functions and ensuring the body's response to various needs, such as adjusting blood cell production in response to oxygen levels. Other choices, such as regulating oxygen levels, digestive enzyme secretion, and neurological function, do not pertain to the primary roles of the kidneys. These functions are handled by different organs and systems, highlighting the kidneys' unique position in endocrine regulation as well as waste removal.