The reabsorption of sodium is also facilitated by the vasoconstriction of

The reabsorption of sodium is also facilitated by the

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of the filtrate. The reabsorption of sodium is also facilitated by the vasoconstriction of afferent arterioles that is initiated by angiotensin II. That decreases the glomerular filtration rate and allows more time for sodium reabsorption. The reabsorption of sodium is so important that it is regulated by a second hormone: atrial natriuretic peptide (ANP). ANP has the opposite affect of aldosterone, inducing a decrease in sodium reabsorption. An increase in the stretch of the atria (due to an increase in atrial pressure) causes an elevation in the secretion of ANP. An increase in ANP induces an increase in glomerular filtration rate by decreasing efferent arteriole resistance through dilation and decreasing the number of open sodium channels in the apical membrane of the principal cell. ANP also decreases the secretion of renin and aldosterone.Diff: 8 Page Ref: 54731
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3) The recovery of potassium from the filtrate that enters Bowman's capsule is an important function of the kidneys. Describe the mechanisms whereby potassium is secreted and/or reabsorbed in each segment of the kidney tubules.
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  • Fall '08
  • BRINN
  • Page Ref, Nephron, loop of Henle

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