The glomerulus, along with its surrounding Bowman's capsule, is called a renal corpuscle.
The renal corpuscle is the initial blood-filtering component of a nephron, which is the functional unit of the kidney. The glomerulus itself is a network of tiny blood vessels (capillaries) responsible for filtering blood. This filtered fluid then passes into Bowman's capsule and onwards through the nephron for further processing to form urine. The overall rate at which blood is filtered by all the glomeruli in the kidneys is known as the glomerular filtration rate (GFR), and this is a key indicator of kidney function.