The organ responsible for filtering blood in the human body is the kidney. Each human has two kidneys, which remove waste products and excess substances from the bloodstream, maintaining overall homeostasis. The kidneys also regulate electrolyte levels, blood pressure, and produce urine. Their functional unit, the nephron, is crucial in the filtration process, allowing for the reabsorption of essential nutrients back into the bloodstream. Kidney health is vital, as dysfunction can lead to serious conditions like kidney disease or kidney failure.