Glomerules

The glomerulus is a tiny, tuft-like structure found within the nephron, the functional unit of the kidney. It is essentially a network of capillaries that serves as the primary site for filtration of blood. Blood enters the glomerulus through the afferent arteriole and exits through the efferent arteriole.

The filtration process in the glomerulus, known as glomerular filtration, is driven by blood pressure. This pressure forces water, small solutes, and waste products from the blood into Bowman's capsule, which surrounds the glomerulus. Larger molecules like proteins and blood cells are retained in the blood and do not pass through the filtration barrier.

The filtered fluid, now called glomerular filtrate, then moves into the renal tubules for further processing. The filtration barrier itself is composed of three layers: the fenestrated endothelium of the capillaries, the glomerular basement membrane, and the podocytes, which are specialized cells of Bowman's capsule. These layers collectively regulate which substances can pass from the blood into the filtrate.

The glomerulus plays a critical role in the formation of urine and the maintenance of homeostasis by removing waste products and excess fluid from the body. Its efficient filtration mechanism is essential for kidney function and overall health.