Kaplan Nursing Entrance Exam Practice 2025 – Comprehensive Prep

The primary function of the kidney in the human body is the production of urine, which plays a crucial role in the excretion of waste products and the regulation of fluid and electrolyte balance. Through the processes of filtration, reabsorption, and secretion, the kidneys filter blood to remove waste and excess substances, which are then concentrated into urine. This urine is stored in the bladder and expelled from the body, thus maintaining homeostasis and preventing the buildup of harmful toxins.

While regulating blood pressure and filtering toxins are also important functions of the kidneys, they are secondary to the process of urine production. The kidneys do contribute to blood pressure regulation through the renin-angiotensin-aldosterone system and play a significant role in detoxifying the blood. Storing minerals is not a direct function of the kidneys; rather, mineral balance is maintained through various mechanisms involving other organs, including the bones and intestines. Therefore, the definition of the primary function aligns closely with the role of urine production in maintaining overall health.