The kidney is one of the most differentiated organs in the body. At the end of embryonic development, almost 30 different types of cells form a multitude of filtration capillaries and segmented nephrons covered by a dynamic interstitium. This cellular diversity modulates various complex physiological processes. Endocrine functions, regulation of blood pressure and intraglomerular hemodynamics, solute and water transport, acid-base balance, and elimination of drug metabolites are achieved by intricate renal response mechanisms.
Renal cells are called nephrons, they are grouped in pyramidal structures or malpighi pyramids in the medullary area of the kidney. They specialize in the purification of the blood plasma of toxic substances originating from the metabolism of proteins such as urea, ammonia and uric acid and their elimination in the form of urine.
Most kidney diseases attack the nephrons, causing them to lose their ability to filter. Damage to the nephrons can occur rapidly, often as a result of injury or poisoning. But most kidney diseases destroy nephrons slowly and silently. Only after years, or even decades, will the damage become apparent. Most kidney diseases attack both kidneys simultaneously. The two most common causes of kidney failure are diabetes and high blood pressure. People with a family history of any type of kidney problem are also at risk for kidney failure.