Which organ is responsible for filtering blood and producing urine?

The kidneys are the organs responsible for filtering blood and producing urine. They play a crucial role in maintaining the body's fluid and electrolyte balance. Each kidney contains approximately one million filtering units called nephrons. As blood passes through the nephrons, waste products and excess substances are removed, while essential nutrients and water are reabsorbed back into the bloodstream. The filtered waste is then transported to the bladder as urine, which is eventually expelled from the body. This vital function helps regulate blood pressure, detoxify the body, and maintain homeostasis.

The heart, while essential for circulating blood throughout the body, does not filter or produce urine. The brain controls many bodily functions, including filtering processes, but it does not engage in the physical filtering of blood or urine production. The liver is important for processing nutrients and detoxifying substances, but it does not perform the specific functions of filtering blood and producing urine, which are primarily the responsibilities of the kidneys.