Autoregulation

Question 1

Renal blood flow, capillary pressure and GFR are….

Answer 1

Maintained almost constant over systemic mean arterial pressure range 90-200mmHg

Question 2

Where does auto regulation even occur?

Answer 2

Even in a denervated and isolated perfused kidney

Constriction and dilation of the arterioles to control GFR is not dependent on nerve supply or blood borne substances

Question 3

Instead constriction and dilation is an….

And how?

Answer 3

Intrinsic property of vascular smooth muscle

Pressure within afferent arteriole rises, stretched vessel wall, triggers contraction of smooth muscle,
Arteriolar constriction

Question 4

The GFR of an individual nephron is regulated by…

Answer 4

The rate at which filtered fluid reaches the distal tubule

Question 5

What do the cells of macula densa do? (Distal tubule)

What do they release?

Answer 5

Detect NaCl arrival

Release prostaglandins in response to reduced NaCl delivery

Question 6

What does the prostaglandins from macula densa cells act on?

Answer 6

Granular cells, triggering renin release thereby activating the RAAS system