Certified Dialysis Nurse Practice Test

The primary function of the kidneys is to filter waste products from the blood. This crucial role involves the kidneys removing toxins, excess salts, and urea through the formation of urine, which is then excreted from the body. The kidneys help maintain homeostasis by balancing electrolytes, regulating blood pressure through the renin-angiotensin system, and controlling the pH level within the body. The filtering process also plays a significant role in maintaining the body's overall fluid balance.

While the kidneys do produce hormones that regulate blood pressure and red blood cell production, this function is secondary to their primary role in waste filtration. Additionally, regulating body temperature is not a function attributed to the kidneys, as that responsibility mainly falls to the hypothalamus and the skin. Storing nutrients is also not a function of the kidneys; instead, nutrient storage is typically managed by the liver and other organs. Thus, filtering waste products is the central function that characterizes the kidneys' role in maintaining health and balance in the body.