The role of the renal capsule is to hold the primary urine produced by the glomerulus and transport it to the renal tubules. There are many glomeruli in the kidneys, and there are many capillaries in the glomeruli, and the blood in the body is then transported through the renal arteries to the capillaries for circulation and filtration. The kidney capsule is a layer of tissue wrapped around the outer layer of the glomerulus. The kidney capsule is composed of two layers of cells, the outer layer is called the wall layer, the inner layer is called the dirty layer, and the middle is called the capsule lumen. The filtered components of the blood will infiltrate into the capsule lumen to form primary urine, which will be transported to the renal tubules through the capsule lumen, so the main role of the capsule is to hold the primary urine and transport it to the renal tubules, similar to the role of the stomach in the digestive system. Acute glomerulonephritis is a lesion of the renal capsule, mainly due to the proliferation of cells in the wall layer and the formation of the crescent, which compresses the glomerulus and causes the loss of filtration function.