Which renal tubule part functions more in secretion?

Correct Answer: C

Rationale: The distal convoluted tubule excels in secretion lacks microvilli (reabsorption-focused), emphasizing secretion (e.g., H , K ) via active transport. The proximal tubule dominates reabsorption ~65% of filtrate (e.g., glucose, Na ) but secretes organics (e.g., creatinine). The Loop of Henle focuses on concentration minimal secretion. The collecting duct adjusts urine via reabsorption/secretion (e.g., H by intercalated cells) less secretion-centric. The distal tubule's secretion role, tied to fine-tuning ion balance, distinguishes it, critical for acid-base and potassium regulation, unlike reabsorption-heavy or concentration-focused segments.

Correct Answer: C

Rationale: Glucose reabsorption is secondary active transport (SGLT) from lumen to cell Na gradient-driven then passive (GLUT) to capillary (e.g., PCT). Passive diffusion alone can't reclaim energy needed. Primary active transport is Na not glucose directly. Full active transport overstates capillary step passive. Dual mechanism distinguishes it, critical for efficient glucose recovery, unlike single-mode errors.

Correct Answer: C

Rationale: Intercalated cells maintain acid-base balance secrete H or HCO₃⁻ in the collecting duct (e.g., pH regulation). Juxtaglomerular cells release renin pressure control. Principal cells manage water/Na ADH/aldosterone. Macula densa senses NaCl GFR feedback. Acid-base role distinguishes intercalated cells, critical for homeostasis, unlike pressure, water, or sensing cells.

Correct Answer: B

Rationale: Principal cells are in connecting tubules (distal/collecting) manage water/Na (e.g., ADH/aldosterone). Intercalated disc is cardiac not renal. Macula densa is distal sensing, not typical connecting. Juxtaglomerular cells are arteriolar renin-focused. Principal cells' presence distinguishes them, key to tubular regulation, unlike misnamed or adjacent cells.

Correct Answer: A

Rationale: Glucose appears before Tmax due to nephron variation heterogeneous Tmax (e.g., some saturate early). Complete reabsorption holds below Tmax false here. Passive reabsorption isn't glucose active. Secretion doesn't apply glucose isn't secreted. Variation distinguishes it, key to splay phenomenon, unlike total or mechanism errors.