What is the function of the kidneys in the human body?

The kidneys are vital organs in the human body responsible for filtering waste and excess substances from the blood to form urine. They regulate fluid and electrolyte balance, maintain blood pressure, and help control the levels of various chemicals, such as sodium, potassium, and calcium. The kidneys also play a role in red blood cell production by secreting erythropoietin, a hormone that stimulates the bone marrow to produce red blood cells. Their ability to filter toxins and maintain homeostasis is essential for overall health.