Kidneys showing bilateral atrophy (tissue wasting)

Kidneys showing marked tissue wasting (bilateral atrophy of the parenchyma). The role of the kidneys is to remove waste products from the blood to form urine, which is then passed down the ureters to the bladder. The atrophy seen here has been caused by hydronephrosis, or the build-up of urine in the kidneys. This condition can be congenital or acquired as a result of blockage of the ureters. Hydronephrosis can increase pressure on the veins, arteries and tissues of the urinary system, causing kidney shrinkage and renal failure.