Your kidneys may be small, but they perform many vital functions that help maintain your overall health, including filtering waste and excess fluids from your blood. Your kidneys have about one million tiny filter units called nephrons. Each nephron has a glomerulus, so that means there are over one million of them too. More than one glomerulus are called glomeruli. Glomeruli work like strainers used in cooking.
While blood moves through them, they let waste and extra water pass into the nephrons to make urine. At the same time, they hold back the protein and blood that your body needs. Many diseases affect kidney function by attacking the glomeruli. When the glomeruli become damaged and cannot do their job, it is called glomerular disease. Glomerular diseases include many conditions with many different causes.