In a patient with volume depletion, which vessel does angiotensin II constrict preferentially in order to maintain the glomerular filtration rate?
Answer and explanation
Correct answer: A. The efferent arteriole
- Step 1: Constricting the efferent arteriole raises glomerular capillary pressure. Step 2. This keeps the GFR up when renal perfusion is low, which is why ACE inhibitors can reduce GFR in renal artery stenosis. Answer: the efferent arteriole. Why not the others: afferent constriction would lower GFR, and the other vessels do not control glomerular pressure.
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