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 vital role in the excretory system, regulating the composition of blood by removing waste products, excess substances, and toxins. As blood passes through the kidneys, specialized structures called nephrons filter out waste while reabsorbing necessary substances back into the bloodstream. This process not only helps eliminate waste but also maintains fluid and electrolyte balance within the body.

The kidneys effectively convert the filtered waste and excess fluids into urine, which is then transported to the bladder for storage until excretion. This filtration and elimination process is essential for maintaining homeostasis, regulating blood pressure, and ensuring the body operates normally.

Other organs listed, such as the liver, heart, and stomach, perform distinctly different functions, including metabolism, circulation, and digestion, respectively, and do not have a direct role in urine production or blood filtration.