Control of Renal Blood Flow

Question 1

• How is GFR maintained relatively stable despite the varying blood pressure?

Answer 1

Autoregulation of renal blood flood

Question 2

• Renal blood flow (RBF) =

Answer 2

Renal plasma flow (RPF) x pack cell volume (PCV)

Question 3

• What two intrinsic processes autoregulate renal blood flow?

Answer 3

Myogenic & tubuloglomerular feedback

Question 4

• What does low pressure lead to?

Answer 4

Vasodilation of afferent arteriole – more blood flow, increased GFR

Question 5

• What vasoactive chemicals are released according to the tubuloglomerular feedback?

Answer 5

Angiotensin II & adenosine – vasoconstriction, prostaglandins & NO – vasodilation

Question 6

• What extrinsic factors kick in if autoregulation fails?

Answer 6

Vasoconstrictors – e.g. SNS & ANG II

Vasodilators – e.g. prostaglandins, NO & bradykinin

Question 7

• What do ACE inhibitors do?

Answer 7

Reduce the activity of the RAAS, decreasing production of ANG II, leading to decreased BP

Question 8

• What will happen to bradykinin?

Answer 8

Bradykinin will increase because of reduced inactivation that is done by ACE