Which of the following is caused after afferent and efferent arterioles constriction by sympathetic activity?

Correct Answer: B

Rationale: Sympathetic constriction of afferent/efferent arterioles lowers GFR less filtration, more Na reaches macula densa (e.g., reduced reabsorption upstream). GFR increase is opposite vasodilation. More Na in PCT reabsorption needs higher flow false. Filtered Na drops low GFR. Macula densa delivery distinguishes it, key to feedback, unlike GFR or reabsorption errors.

Correct Answer: A

Rationale: Rising [H ] lowers pH acidosis (e.g., pH = -log[H ]). pH increase is alkalosis opposite. Increased pH with acidosis contradicts false. Fallen pH with alkalosis reverses incorrect. Acidosis link distinguishes it, key to pH definition, unlike reversed or mixed errors.

Correct Answer: D

Rationale: Compensated metabolic alkalosis shows high PCO₂ (hypoventilation), high HCO₃⁻ (primary), high pH lungs retain CO₂ to offset (e.g., vomiting). Low PCO₂ is uncompensated acute. Low HCO₃⁻/pH is acidosis opposite. High PCO₂/low pH is respiratory acidosis unrelated. Compensation distinguishes it, key to acid-base balance, unlike uncompensated or opposite states.

Correct Answer: C

Rationale: The glomerulus filters blood into Bowman's capsule not loop of Henle (reabsorption), ureter (transport), or collecting duct (concentration). This pinpoints filtration site, critical for GFR, contrasting with later nephron segments.

Correct Answer: B

Rationale: The urethra expels urine from the body not ureter (kidney to bladder), nephron, or loop (kidney). This defines excretory channel, critical for elimination, contrasting with internal structures.