The kidneys play an important role in the body as they are responsible for filtering the blood and removing waste products and excess water. These are then excreted from the body via the urinary system in the form of urine. The waste products found in the bloodstream come from the breakdown of tissues, cells and the food you take into your body. Once the body has obtained what it requires from the food you eat, waste will be directed to the blood and carried to the kidneys. If the kidneys are not functioning well the waste will build-up and this can cause damage to the body.
Kidney disease is an abnormal structure, function or process in the kidney(s). Nephrosis is non-inflammatory nephropathy and nephritis is inflammatory kidney disease. Nephrology is the speciality that deals with kidney function and disease. Medical terms related to the kidneys commonly use terms such as renal and the prefix nephro- . The adjective renal , meaning related to the kidney, is from the Latin rēnēs , meaning kidneys; the prefix nephro- is from the Ancient Greek word for kidney, nephros (νεφρός) .  For example, surgical removal of the kidney is a nephrectomy , while a reduction in kidney function is called renal dysfunction .