In a 3-6 hour hemodialysis, how much urea can be removed from a patient?

Correct Answer: B

Rationale: Hemodialysis removes 8-25 g urea in 3-6 hours e.g., typical clearance (blood levels drop). 8-10 g is low underestimates. 50-250 g is excessive beyond capacity. 8-25 mg is trivial mg vs. g error. 8-25 g distinguishes it, critical for dialysis efficacy, unlike under/over or unit mistakes.

Correct Answer: B

Rationale: In alkalosis, kidneys excrete HCO₃⁻ less CO₂ binding allows loss (e.g., distal tubule adjustment). More Na reabsorption doesn't fix base excess unrelated. Angiotensin/ADH affects water not pH directly. K absorption is minor irrelevant. HCO₃⁻ excretion distinguishes it, critical for pH correction, unlike Na or K shifts.

Correct Answer: B

Rationale: Kidney innervation (sympathetic) regulates arteriole diameter e.g., constricts afferent/efferent, adjusts GFR. Filtrate composition is glomerular not neural. Water reabsorption is hormonal (ADH) not innervation. Brush border is structural not regulated. Arteriolar control distinguishes it, key to blood flow, unlike filtrate or tubular functions.

Correct Answer: B

Rationale: Aldosterone is secreted by zona glomerulosa e.g., adrenal cortex, boosts Na reabsorption. Adjacent to macula densa is JGA not aldosterone. Tube is ureter unrelated. Hypothalamus synthesizes ADH not aldosterone. Adrenal origin distinguishes it, key to its role, unlike JGA or hypothalamic errors.

Correct Answer: A

Rationale: Renin is secreted by JG cells e.g., JGA responds to low BP. Ureter transports not secretes. Hypothalamus makes ADH not renin. Micturition is urination unrelated. JG secretion distinguishes it, key to BP regulation, unlike tubes or actions.