Basic Functions
The kidneys are essential for homeostasis (maintaining a constant internal environment) of the body's extracellular fluids. Their basic functions include:
1. Regulation of extracellular fluid volume. The kidneys work to ensure an adequate quantity of plasma to keep blood flowing to vital organs.
2. Regulation of osmolarity. The kidneys help keep extracellular fluid from becoming too dilute or concentrated with respect to the solutes carried in the fluid.
3. Regulation of ion concentrations. The kidneys are responsible for maintaining relatively constant levels of key ions including sodium, potassium and calcium.
4. Regulation of pH. The kidneys prevent blood plasma from becoming too acidic or basic by regulating ions.
5. Excretion of wastes and toxins. The kidneys filter out a variety of water-soluble waste products and environmental toxins into the urine for excretion.
6. Production of hormones. The kidneys produce erthryopoietin, which stimulates red blood cell synthesis, and renin, which helps control salt and water balance and blood pressure. They are also involved in regulating plasma calcium and glucose levels.
