Which of the following has a function in maintaining the acid-base balance of the body?

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: 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.

Correct Answer: B

Rationale: Sodium entering the tubule at the luminal membrane is false enters cell from lumen, exits to blood (e.g., PCT). Early reabsorption is true ~65%. Na /K -ATPase drives active exit passive misstated but mechanism holds. All correct overstates entry error. Direction distinguishes the falsehood, key to Na transport, unlike location or pump truths.

Correct Answer: A

Rationale: Thirst center activates with 10-15% plasma volume drop or 1-2% osmolarity rise sensitive triggers (e.g., hypothalamus). 1-2% volume or 10-15% osmolarity reverses thresholds incorrect. Thirst is result not stimulus. ADH is parallel not cause. Precise thresholds distinguish it, key to thirst drive, unlike reversed or effect-based options.

Correct Answer: C

Rationale: With ADH, water reabsorption in collecting duct is passive osmosis via aquaporins (e.g., medullary gradient). Active transport is Na not water. Cortical-only mislimits medullary too. All passive distinguishes it, key to ADH's osmotic drive, unlike active or partial errors.