What are the functions of the kidneys?
They filter blood plasma, separate wastes from the useful chemicals and eliminate the waste while returning the rest to the bloodstream. They regulate blood volume and pressure by eliminating or conserving water.The kidneys help regulate the concentration of major ions such as Na+, Cl-, K+, Ca+, and HPO4-2.They secrete variable amounts of H ions to help regulate the extracellular fluid pH. The kidneys secrete a hormone, erythropoietin, which regulates the synthesis of red blood cells in bone marrow. They play a important role in controlling blood levels of Ca2+ by regulating the synthesis of vitamin D.