The Bowman's capsule is the origin of the nephron, which is the functional unit of the vertebrate kidney (yes, that means it's in humans). The Bowman's capsule receives blood plasma from the glomerulus. The glomerulus is nested inside the Bowman's capsule. The blood plasma is forced from the glomerulus through the process of ultrafiltration. This is the beginning of the production of urine in the body. The blood plasma is called filtrate once it enters the Bowman's capsule, and is similar to the composition of blood plasma. However, it lacks proteins because of their large size. The filtrate the Bowman's capsule produces will become urine after a long process of reabsorbing water and other stuff in it, and also adding other wastes. The Bowman's capsule is in the shape of a hollowed out ball, and ducts to the proximal convoluted tubule. It may also be called the glomerular capsule.