glomerulusons
A glomerulus is a small, tangled cluster of capillaries within the kidney. This structure is the primary site for filtration of blood in the nephron, the functional unit of the kidney. Blood enters the glomerulus through the afferent arteriole and leaves through the efferent arteriole. The high pressure within the glomerular capillaries forces water and small solutes from the blood into Bowman's capsule, the cup-shaped structure that surrounds the glomerulus. This filtered fluid, known as the glomerular filtrate, then passes into the renal tubules for further processing. The filtration process is selective, allowing small molecules like water, electrolytes, glucose, and urea to pass through, while retaining larger molecules such as proteins and blood cells in the blood. The rate at which blood is filtered through the glomeruli is called the glomerular filtration rate (GFR), a key indicator of kidney function. Abnormalities in glomerular structure or function can lead to various kidney diseases, including glomerulonephritis.