Control of Renal Blood Flow Flashcards Preview

Pulmonary and Renal Physiology > Control of Renal Blood Flow > Flashcards

Flashcards in Control of Renal Blood Flow Deck (21):
1

What is clearance of PAH used for?

Measuring renal plasma flow.

2

How to calculate RBF?

RBF = RPF/ (1-Hct)

3

Two main categories regulation of renal blood flow?

Vascular and Non-Vascular

4

Where in the vasculature is RBF regulated?

Afferent and Efferent arterioles.

5

Effect of Constricting/Relaxing Afferent Arteriole

Constrict: Decrease Renal Blood Flow, Decrease GFR
Relax: Increase Renal Blood Flow, Increase GFR

6

Filtration Fraction Definition and Equation

The percentage of delivered plasma that is filtered at the capillary. FF=GFR/RPF

7

Effect of Constricting/Relaxing Efferent Arteriole

Constrict: Decrease Renal Blood Flow, Increase Filtration Fraction, Increase GFR.
Relax: Increase Renal Blood Flow, Decrease Filtration Fraction, Decrease GFR.

8

How does FF affect proximal tubule reabsorption?

Increasing FF will increase hydrostatic pressure of the glomerular capillary, which will cause an increase in osmotic pressure of the glomerular capillary, which will increase the osmotic pressure of the peritubular capillary. This will drive reabsorption of H2O.

9

Effect of Sympathetic Output on Renal Vasculature, RBF, and GFR

Constriction of afferent and efferent arterioles.
Decrease in RBF.
No change in GFR (maybe a little reduced).

10

Effect of AngII on Renal Vasculature

Constriction of afferent and efferent arterioles, with a slight preference for efferent.
Decrease in RBF
No change in GFR (maybe a little reduced).

Also causes mesangial cell contraction

11

Effect of ANP on Renal Vasculature

Dilation of afferent arteriole, constriction of efferent arteriole.
No change in RBF (opposite effects).
GFR increases.

12

Affect of Histamine on Renal Vasculature

Dilation of afferent and efferent arterioles.
RBF increases.
No change in GFR.

13

Affect of EDRF/NO on Renal Vasculature

Afferent dilation only.
No change in RBF.
Increased GFR.

14

Does ADH have an effect on renal vasculature?

Not really.

15

Effect of Endothelin on Renal Vasculature

Constriction of afferent and efferent arterioles (preference for afferent).
RBF decreases.
GFR decreases.

16

Effect of PGE2 and PGI2 on Renal Vasculature

Dilation of afferent arterioles.
RBF increases.
GFR increases.

17

Nonvascular regulation of RBF and GFR

Mesangial cell contraction, maybe podocyte contraction?

18

What does mesangial cell contraction do to RBF and GFR?

Contraction of mesangial cells causes basement membranes to contract, reducing SA, which decreases Kf, and decreases GFR.

19

Autoregulation of GFR and RBF

When BP rises, the afferent capillary will constrict (increasing renal vascular resistance) to maintain RBF and GFR. Controlled by NO, myogenic mechanism, but mostly tubuloglomerular feedback.

20

Myogenic mechanism of autoregulation

As renal arterioles get stretched, they will contract with greater force. This is a passive process.

21

Tubuloglomerular feedback mechanism of autoregulation

Increase in GFR will cause an increase in tubular flow. Flow past macula densa cells increases, causes release of adenosine onto afferent arteriole causing constriction.