Renal autoregulation:
Ans. D. Minimizes the impact of changes in arterial blood pressure on renal Na+ excretionIn the autoregulatory range, vascular resistance falls when arterial blood pressure falls. Changes in vessel caliber primarily occur in vessels upstream to the glomeruli (cortical radial arteries and afferent arterioles). Because autoregulatory range extends from an arterial blood pressure of about 80 to 180 mm Hg, renal blood flow is not maintained when blood pressure is low; in fact, the sympathetic nervous system will be activated and cause intense vasoconstriction in the kidneys. Renal autoregulation does not depend on nerves.
Is associated with increased renal vascular resistance when arterial blood pressure is lowered from 100 to 80 mm Hg
Mainly involves changes in the caliber of efferent arterioles
Maintains a normal renal blood flow during severe hypotension (blood pressure, 50 mm Hg)
Minimizes the impact of changes in arterial blood pressure on renal Na+ excretion
Heart, Circulation, and Blood