Which structure serves as the site of filtration in the vertebrate kidney?

Which structure serves as the site of filtration in the vertebrate kidney?

• A. Glomerulus
• B. Bowman's capsule
• C. Ureter
• D. Renal pelvis

Answer: (A)

Filtration happens at the glomerulus, a tuft of capillaries inside the nephron’s renal corpuscle. Blood pressure forces water and small solutes across the filtration barrier—the fenestrated capillary endothelium, the basement membrane, and the podocyte slit diaphragms—into Bowman's space. This area is the actual filtration site, producing the initial filtrate that will be processed further along the nephron. Bowman's capsule simply collects that filtrate, while the ureter and renal pelvis are involved in transporting urine, not filtration.

Filtration happens at the glomerulus, a tuft of capillaries inside the nephron’s renal corpuscle. Blood pressure forces water and small solutes across the filtration barrier—the fenestrated capillary endothelium, the basement membrane, and the podocyte slit diaphragms—into Bowman's space. This area is the actual filtration site, producing the initial filtrate that will be processed further along the nephron. Bowman's capsule simply collects that filtrate, while the ureter and renal pelvis are involved in transporting urine, not filtration.