Which cells of the JGA act as mechanoreceptors?

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: 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.

Correct Answer: C

Rationale: Capsular space isn't part of the filtration membrane it's the filtrate receptacle (Bowman's space). Fenestrated endothelium, visceral membrane (podocytes), and filtration slits (with basement membrane) form the barrier plasma filters through. Space as destination distinguishes it, critical for filtration anatomy, unlike structural components.

Correct Answer: A

Rationale: Glomerular hydrostatic pressure (~55 mmHg) pushes fluid out drives filtration (e.g., Starling force). Back into vessels is oncotic/capsular opposes. No effect ignores its role false. Varying with oncotic misaligns independent. Outward push distinguishes it, critical for GFR, unlike opposing or neutral errors.

Correct Answer: A

Rationale: The proximal tubule is the primary site for organic ion secretion e.g., urate, creatinine via transporters (e.g., OATs). Loop of Henle concentrates minimal secretion. Distal tubule secretes H /K less organic. Collecting duct adjusts not primary. Proximal dominance distinguishes it, key to waste excretion, unlike later segments.