Question

How do kidneys respond to reduced blood flow?

Answer 1

Kidney flow:

1. When renal blood flow is compromised, the kidneys react by secreting prostaglandins and angiotensin II.
2. Angiotensin II has a vasoconstrictor effect on the renal efferent arterioles of the renal kidneys.
3. Vasodilator activity of prostaglandins has an effect on afferent arteriole of the renal kidney.
4. Hence, these hormones help in preserving the filtration rate of the glomerulus.
5. RBF originates in the hilum of the kidney via the renal artery.
6. Under conditions of renal hypoperfusion or renal impairment, the administration of a combination of NSAIDs with ACE inhibitors will interfere with these physiological compensatory mechanisms, and so cause acute impairment of renal function through a fall in glomerular filtration by combined renal blood flow changes.
7. NSAIDs inhibit dilatation by renal prostaglandins and the vasoconstrictor effect on the efferent arterioles is inhibited by ACE inhibitors.