What is the primary function of the glomerulus in Bowman's capsule of the nephron?

The primary function of the glomerulus within Bowman's capsule of the nephron is filtration of blood. The glomerulus is a network of tiny capillaries where blood enters under pressure. This high pressure forces water, ions, small molecules, and waste products from the blood plasma into Bowman's capsule, forming a filtrate. This process is crucial as it initiates the formation of urine by separating substances that need to be excreted from those that should be retained in the bloodstream.

The filtration process is selective, allowing only certain substances to pass through while keeping larger molecules, such as proteins and blood cells, in the bloodstream. This initial filtration is the first step in renal function and significantly contributes to regulating body fluid composition, electrolyte balance, and waste elimination.