The part of the Loop of Henle which is permeable to water is?

Correct Answer: C

Rationale: The thin descending limb is water-permeable osmosis concentrates filtrate (e.g., medullary gradient). Thick ascending is impermeable pumps NaCl. Thin ascending loses salt not water. All permeable is false ascending resists. Water permeability distinguishes thin descending, critical for countercurrent, unlike impermeable or mixed options.

Correct Answer: C

Rationale: ADH is synthesized in supraoptic/paraventricular hypothalamic nuclei transported to posterior pituitary (e.g., magnocellular neurons). Posterior pituitary stores/releases not synthesizes. Anterior pituitary is ACTH/GH unrelated. Neurohypophysis is synonymous less specific. Hypothalamic origin distinguishes it, critical for ADH production, unlike pituitary errors.

Correct Answer: D

Rationale: Increased ventilation decreases extracellular COâ‚‚ blows off COâ‚‚, raising pH (e.g., respiratory alkalosis). Intracellular H lowering is secondary pH effect. Intracellular COâ‚‚ shifts less direct. Extracellular H decrease follows COâ‚‚ primary. COâ‚‚ reduction distinguishes it, key to ventilatory pH shift, unlike H or intracellular focus.

Correct Answer: C

Rationale: Laryngeal obstruction won't cause respiratory alkalosis blocks ventilation, raising PCOâ‚‚ (acidosis). Fever, anxiety, and salicylate toxicity hyperventilate lower PCOâ‚‚, raise pH. Obstruction's acidotic effect distinguishes it, critical for respiratory differential, unlike alkalosis triggers.

Correct Answer: B

Rationale: Nephrons filter blood and form urine not transport (ureters), absorb nutrients (gut), or store waste (bladder). This defines their role, key for renal function, contrasting with downstream or unrelated tasks.