Specify one factor affecting sodium reabsorption.

Correct Answer: B

Rationale: Aldosterone is a key factor affecting sodium reabsorption. This hormone, released from the adrenal cortex, acts on principal cells in the collecting duct and distal tubule, increasing Na⁺/K⁺-ATPase and epithelial sodium channel (ENaC) activity. This enhances Na⁺ reabsorption, retaining salt and water to raise blood volume and pressure. While GFR, estrogens, and natriuretic hormone also influence Na⁺ handling, aldosterone's direct and potent effect makes it a standout choice, thus B is correct.

Correct Answer: A

Rationale: The hypothalamic thirst center is activated by significant triggers: a 10-15% drop in plasma volume (hypovolemia) or a 1-2% rise in plasma osmolality (hyperosmolality), detected by osmoreceptors and baroreceptors. These thresholds prompt thirst to restore fluid balance. Smaller changes (B) are insufficient, and C and D are outcomes, not stimuli, making A correct.

Correct Answer: C

Rationale: In bicarbonate buffering, excess H⁺ binds with HCO₃⁻ to form H₂CO₃ (C), which then dissociates into CO₂ and H₂O (A), exhaled by lungs. This sequence neutralizes acid. HCO₃⁻ isn't converted to H₂CO₃ first (B), and ‘all' (D) ignores order, making C the correct initial step.

Correct Answer: C

Rationale: Anger in a new cancer diagnosis reflects grief or fear. Directing the discussion and validating emotions (C) (e.g., 'I see you're upset, let's talk about it') de-escalates tension without false promises. Time alone (A) may isolate, peer talks (B) lack control, and social work (D) delays immediate response, making C the best approach.

Correct Answer: C

Rationale: Calcium channel blockers typically reduce bladder contractility, potentially causing retention, not increased elimination (C), warranting education. Diuretics (A), anticholinergics (B), and alpha blockers (D) are correct, as they respectively increase output, reduce urgency, and improve flow, making C the inaccurate statement.