What is the primary function of the kidneys?

The primary function of the kidneys is to conserve what is beneficial to the body. This involves a complex process of filtration and reabsorption. As blood passes through the kidneys, waste products, excess minerals, and water are removed, forming urine. However, the kidneys also play a crucial role in reabsorbing essential substances such as glucose, certain ions, and proteins, which are valuable for maintaining the body's homeostasis.

Additionally, the kidneys help maintain the balance of electrolytes and acid-base levels in the body, which is vital for many physiological processes. While functions such as regulating blood pressure and excreting excess water are part of the kidneys' roles, their overarching duty remains the conservation of substances that the body requires for optimal functioning. This intricate balance ensures that the body's internal environment remains stable, regardless of external changes.