The fact that the basic structure and function of the kidneys is similar in all the major groups of animals with backbones (vertebrates) shows that they play a critical role in our survival. There are a number of kidney functions but here are the most important:
- Toxin Removal: Your body is constantly accumulating toxins either coming from your food or being made as waste products by your cells. Many of these toxins would be fatal if they were allowed to build up in the body. The kidney breaks down and/or removes many of them from the body by getting rid of it in the urine.
- Drug Removal: Many drugs are either broken down and/or removed in the urine. Many drugs need to have their dosages reduced (some stopped) when the kidneys fail.
- Fluid Balance: The body is constantly gaining fluid (from the diet) and losing it (evaporation, urine, stool). Too little fluid and you become dehydrated; too much fluid and you swell up and can’t breathe.
- Electrolyte Balance: In order for cells to function properly, the concentration of electrolytes in the blood need to be tightly controlled. Here are the most important electrolytes and the organs that are particularly sensitive to their changes:
- Sodium (Na) – Brain and nerves
- Potassium (K) – Heart, muscle and nerves
- Calcium (Ca) – Heart, muscle, nerves, and bone
- Magnesium (Mg) – Heart. muscle and nerves
- Phosphorus (PO3) – Muscles and bones
- Acid-Base Balance: A protein’s structure and function is very sensitive to changes in acid concentration (pH). The kidneys need to remove the extra acid that the body makes.
- Blood Pressure Control: The kidneys are responsible for making sure that blood pressure is stable over the long term. It is said that high blood pressure cannot exist for long if the kidneys did not let it happen.
- Hormone Production: In addition to the hormones produced for the functions described above, the kidneys are responsible making two important others:
- Vitamin D – Used to harden or mineralize bone in addition to calcium and phosphorous balance.
- Erythropoietin (EPO) – Tells the bone marrow to make more red blood cells.
