Selective Reabsorption - GCSE Biology Definition

Selective reabsorption is a process that happens in the kidneys during the filtration of blood. After the blood is filtered, useful substances like glucose, certain ions, and water are reabsorbed back into the bloodstream from the kidney tubules. This process ensures that only waste products and excess substances are removed in the urine, while the body retains the important substances it needs to function properly. Selective reabsorption relies on tiny structures called nephrons in the kidneys, which carefully decide what to keep and what to let go, helping to maintain a balance of fluids and nutrients in the body.