Which renal structure is a network of capillaries involved in filtration?

Which renal structure is a network of capillaries involved in filtration?

• A. Glomerulus
• B. Renal tubule
• C. Collecting duct
• D. Ureter

Answer: (A)

Filtration in the kidney happens in the glomerulus, a tuft of capillaries tucked inside Bowman's capsule. Blood enters via the afferent arteriole and is pushed through a filtration barrier made of fenestrated endothelium, the glomerular basement membrane, and podocyte slit diaphragms. This barrier lets water, ions, and small solutes pass into Bowman's space to form the filtrate, while keeping larger components like blood cells and most proteins in the circulation. The filtrate then moves into the renal tubule for reabsorption and secretion, ultimately forming urine. The other structures have different roles: the renal tubule reclaims fluids and solutes, collecting ducts concentrate urine under hormonal control, and the ureter transports urine to the bladder.

Filtration in the kidney happens in the glomerulus, a tuft of capillaries tucked inside Bowman's capsule. Blood enters via the afferent arteriole and is pushed through a filtration barrier made of fenestrated endothelium, the glomerular basement membrane, and podocyte slit diaphragms. This barrier lets water, ions, and small solutes pass into Bowman's space to form the filtrate, while keeping larger components like blood cells and most proteins in the circulation. The filtrate then moves into the renal tubule for reabsorption and secretion, ultimately forming urine. The other structures have different roles: the renal tubule reclaims fluids and solutes, collecting ducts concentrate urine under hormonal control, and the ureter transports urine to the bladder.