The glomerulus is a tiny, ball-shaped cluster of capillaries located in the kidneys. It plays a crucial role in the filtration of blood, helping to remove waste products and excess substances. Each kidney contains about a million glomeruli, which are part of the nephron, the functional unit of the kidney. During the filtration process, blood flows into the glomerulus, where water, ions, and small molecules pass through its walls into the surrounding capsule, known as the Bowman's capsule. This filtered fluid then continues through the nephron for further processing, ultimately leading to the formation of urine.