Ultrafiltration in the kidney takes place in the Bowman's capsule. The Bowman's capsule is a cup-shaped structure at the beginning of the nephron in the kidney. It contains a cluster of blood vessels called the glomerulus, which is surrounded by a space called the Bowman's space. When blood enters the glomerulus, it is filtered under pressure and the filtrate (which contains water, ions, glucose, and waste products) enters the Bowman's space. This process is known as ultrafiltration and is the first step in the formation of urine. The filtrate then moves through the rest of the nephron, where it is modified and eventually excreted from the body as urine.