How much fluid is filtered by the nephrons in one day?

Correct Answer: C

Rationale: Nephrons filter ~180 L/day GFR ~125 mL/min × 1440 min (e.g., normal adult). 10 L underestimates far too low. 100 L is half insufficient. 200 L overestimates exceeds typical. 180 L distinguishes it, critical for renal workload, unlike under/overestimates.

Correct Answer: A

Rationale: Hormones (aldosterone, ADH) control distal tubule salt/water reabsorption e.g., Na via ENaC, water via aquaporins. NaCl is reabsorbed not controller. Glucose is PCT not distal. Urea is medullary not regulatory. Hormonal regulation distinguishes it, key to fine-tuning, unlike substrates.

Correct Answer: A

Rationale: Hyperventilation rids excess H blows off COâ‚‚, raising pH (e.g., respiratory alkalosis). Hypoventilation retains COâ‚‚ worsens. Urination is slow kidneys lag. Holding breath increases COâ‚‚ opposite. Hyperventilation's speed distinguishes it, key to acute pH correction, unlike retention or slow methods.

Correct Answer: B

Rationale: Urea is produced in the liver protein breakdown via urea cycle (e.g., ammonia detox). Muscles produce creatinine not urea. Kidneys excrete not synthesize. Spleen is immune not metabolic. Liver's production distinguishes it, key to nitrogen handling, unlike muscle, kidney, or spleen roles.

Correct Answer: B

Rationale: Glucose reabsorption occurs fully in proximal tubules e.g., SGLT transporters reclaim all (~180 g/day). Insulin aids uptake not tubular reabsorption. Metabolism doesn't vary it threshold fixed. Liver regulates blood glucose not tubules. PCT's complete reabsorption distinguishes it, critical for glucose retention, unlike hormonal or metabolic control.