What is the main function of the kidneys?

The primary function of the kidneys is to filter blood and create urine. This process is crucial for maintaining homeostasis within the body. The kidneys remove waste products and excess substances from the bloodstream, which helps regulate electrolyte balance, fluid volume, and acid-base balance. The filtrate produced in the kidneys is eventually excreted as urine. Through this filtration process, the kidneys effectively remove toxins and other unwanted materials, ensuring that the body's internal environment remains stable and healthy.

In addition to waste removal, the kidneys also play a role in regulating blood pressure and producing certain hormones, such as erythropoietin, which stimulates red blood cell production. However, their main role is undeniably related to the filtration of blood and the formation of urine. This is essential for overall kidney function and the body's ability to manage metabolic waste.