Nephrons are the filtering structures of the kidneys. The kidneys contain millions and millions of these tiny filtering structures that are responsible for cleaning the blood. Nephrons are responsible for removing excess water, wastes, and other substances in the blood that are not needed by the body. They also return necessary substances (e.g. sodium, potassium, phosphorus) whenever the body runs low in supply.
If these nephrons are damaged, blood will not be properly filtered. As a result, the kidney will have different diseases and this might lead to kidney and multiple organ failure.