15B-48

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Question

Sympathetic nervous system
A. Increases Na reabsorption in the proximal tubule
B. Increases efferent arteriole tone to decrease GFR
C. Decreases renin release
D. Something about the collecting ducts

Comments

ANSWER B

A: INCORRECT: decreases GFR so Na reabsorption will decrease
B: CORRECT: SNS constricts afferent & efferent arterioles -> reduce RBF + GFR (Power & Kam, 2nd ed, p228)
C: INCORRECT: Increases renin release, direct β1 effect
D: INCORRECT
Dr mitta 18:07, 15 November 2015 (CST)


I think A is correct - p109 Vander 'proximal tubule epithelial cells are innervated by alpha1 and alpha2 adrenergic receptors. Stimulation of these in proximal tubule by norepinephrine activates both components of the main transcellular sodium reabsorptive pathway in the apical membrane and the Na-K_ATPase in the basolateral membrane'. If B said increases afferent arteriole tone to decrease GFR may be more difficult...

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