Which organ is primarily responsible for filtering blood?

The kidneys play a crucial role in filtering blood, primarily by removing waste products and excess substances from the bloodstream. They filter approximately 50 gallons of blood daily, ensuring that waste products such as urea and creatinine, along with excess salts and water, are eliminated from the body through urine. The kidneys are made up of functional units called nephrons, which are specifically designed for filtration and reabsorption processes. These processes help maintain the body's electrolyte balance, regulate blood pressure, and contribute to overall fluid balance in the body.

While the liver, lungs, and pancreas have vital functions in the body, their roles are distinct. The liver is involved in detoxifying blood, metabolizing nutrients, producing bile, and storing glycogen. The lungs facilitate gas exchange but do not filter blood in the same way as the kidneys. The pancreas primarily produces digestive enzymes and hormones, such as insulin, but does not participate in blood filtration. Thus, the kidneys are clearly identified as the primary organ responsible for filtering blood.