The micturition reflex center is located in the _____.

Correct Answer: D

Rationale: Micturition reflex is in sacral plexus (S2-S4) not pons, midbrain, or lumbar. This locates control, key for voiding, contrasting with higher centers.

Correct Answer: A

Rationale: PCT removal halts ~65% reabsorption, stopping urine formation not unaffected, concentrated, or diluted. This underscores PCT role, critical for processing, contrasting with later adjustments.

Correct Answer: B

Rationale: Juxtaglomerular cells in the JGA act as mechanoreceptors sense afferent arteriole pressure (e.g., stretch), releasing renin to adjust GFR. Macula densa cells are chemoreceptors monitor NaCl, not pressure. Intercalated cells (collecting duct) manage acid-base no JGA role. Principal cells (collecting duct) handle water/Na unrelated. Juxtaglomerular cells' pressure-sensing distinguishes them, critical for autoregulation, unlike chemical or distant tubular cells.

Correct Answer: C

Rationale: A -10 mmHg NFP means no filtration forces opposing (oncotic + capsular, 40 mmHg) exceed driving force (hydrostatic, 30 mmHg), halting GFR (e.g., shock). Normal filtration needs positive NFP (~10 mmHg). Increased filtration requires higher positive e.g., hypertension. High reabsorption is tubular not glomerular. Lack of filtration distinguishes it, critical for acute renal failure risk, unlike normal or enhanced filtration.

Correct Answer: C

Rationale: The thin descending limb is highly water-permeable osmosis concentrates filtrate (e.g., medullary gradient). Thick ascending limb is impermeable actively pumps NaCl. Thin ascending limb is less permeable salt exits. Thick descending isn't a segment error. Water permeability distinguishes the thin descending, critical for countercurrent multiplier, unlike salt-focused or misnamed parts.