Filtration from the blood into the nephron occurs initially into which structure?

• A. Bowman's capsule
• B. Proximal tubule
• C. Loop of Henle
• D. Collecting duct

Answer: (A)

Filtration from the blood into the nephron first happens when plasma is pushed through the glomerular filtration barrier into Bowman's capsule, forming the filtrate that enters the nephron. The glomerulus acts like a sieve, allowing water and small solutes to pass while keeping larger proteins and cells in the blood. This filtrate collects in Bowman's space within Bowman's capsule and then moves downstream to the proximal tubule for reabsorption and further processing. The other nephron segments (loop of Henle and collecting duct) handle reabsorption, secretion, and concentration after filtration has occurred.