Renal: 14. Hamra : Renal Blood Flow And Gfr

Front 1

renin-producing granular cells do what? where are they located?

Back 1

sense pressure, reduce store and release rennin

in afferent arteriole

Front 2

macula densa

Back 2

salt sensor of the nephron

Front 3

extraglomeular mesangial cells

Back 3

can contract or relax dependent on endogenous substances

Contraction of these cells may restrict flow through some of the capillary loops, thus effectively reducing the area available for filtration (thus a decrease in Kf) and thus a decrease in GFR

Front 4

what is GFR and normal?

Back 4

The volume of filtrate formed per unit time
Don’t forget the units…VOLUME/TIME

norm = 180L/Day

Front 5

Rate of filtration =?

Back 5

Kf x NFP

Kf= hydraulic permeability X surface area (thi sis the filtration coefficient)

NFP= Net filtration pressure

Front 6

NFP =

Back 6

net filtration pressure

(PGC-PBC-OncoticGC)

PGC= glomerular capillary hydrostatic pressure

PBC= Bowman's capsule hydrostatic pressure

PieGC= Glomeruluar capillary oncotic pressure

Front 7

if you relax the glomeruluar mesangial cells, what will this do to Kf?

Back 7

this increases Kf

so according to Kf x NFR= GFR

this increases the GFR

Front 8

FINISH TABLE 2-2

Back 8

SLIDE 11

have to know it

Front 9

if you increase the afferent arteriole resistant, what does it do to PGC? what does this mean for GFR?

Back 9

decrease PGC

decrease GFR

Front 10

if you increase the efferent arteriole resistant, what does it do to PGC? what does this mean for GFR?

Back 10

increase PGC

increase GFR

Front 11

if you decreases renal plasma flow what happens to GFR?

Back 11

When the flow is slow you will get a rapid increase in oncotic GC…this can mean that you stop filtration b/c the oncontic GC opposes filtration

according to Kf x NFP

you will decrease GFR

Front 12

Filtration factor=

Back 12

GFR/RPF

Front 13

Filtration factor is greater at low or high plasma flow?

Back 13

LOW

FF=GFR/RPF

Front 14

if you increase afferent arteriole resistance, what does this do to RBF?

Back 14

decrease

Front 15

if you increase efferent arteriole resistance, what does this do to RBF?

Back 15

decrease

Front 16

if you increase afferent AND efferent arteriole resistance, what does this do to RBF?

Back 16

decrease

Front 17

how is it possible to constrict the efferent arteroile and cause increase GFR and decrease RBF?

Back 17

when you vasoconstrict you will increase GFR up to a certain point, yet as RBF starts to decrease, you will reach a threshold where you will not have enough RBF to cause an increase in GFR...

Front 18

With SNS stimulation (and angiotensin II), BOTH afferent and efferent resistances _____ and RBF _____

Back 18

increase

decrease

Front 19

when you have an increase in RAAS after volume depletion the combined effect will do what to GFR?

Back 19

it will be maintained

even though you decrease RBF

this was on a test before..worth knowing that when you have volume depletion and you activate RAAS that GFR will be maintained

Front 20

You give a person a drug that dilates the afferent arteriole and constricts the efferent arteriole by the same amounts.

What effect will this have on GFR, RBF, and FF?

Back 20

GFR= increase

RBF= no change

FF= increase

in spite of the fact that you have that PGC effect to increase GFR, FF is increasing oncotic pressure (you are leaving proteins left behind in the capillary), this will blunt the effect GFR

Front 21

Your patient has entered the ER after a motorcycle accident. His blood pressure is very low and he is tachycardic. You believe he has lost a great deal of blood volume.

What will happen to RAAS?

What about FF?

Back 21

RAAS will increase

FF will increase after RAAS

Front 22

Your patient has renal artery stenosis. What effect will the stenosis have on RAAS and subsequently on GFR?

Back 22

increase RAAS

maintain GFR

angiotension works right where you have that threshold of constricting the efferent arteriole that sets RBF and PGC about equal...

Front 23

what is they myogenic response and where does it occur?

Back 23

increase in BP that would increase the RBF, you get a vasoconstriction to maintain RBF to maintain GFR

this also works in the reverse for low BP

THIS HAPPENS AT THE AFFERENT ARTERIOLE****

note this only blunts the effect

Front 24

effects of RAAS/SNS on RBF and GFR

Back 24

RAAS system: Ang II constricts afferent and efferent arterioles (efferent more than afferent)
SNS: constricts both afferent and efferent arterioles
Net effect: decrease in RPF w/ only a little or no change in GFR

Front 25

what does ADH do to RBF and GFR?

Back 25

does vasoconstrict, but normally RBF and GFR remain constant

Front 26

what does ANP do to GFR and RBF?

Back 26

afferent dilation, thus causes increases in both GFR and RBF; also inhibits the secretion of renin

Front 27

low dose dopamine does what

Back 27

causes low dose vasodilation

Front 28

generally protective against excessive vasoconstriction like the excess you might see with lots of SNS and ANG II...this describes?

Back 28

Prostaglandins

Front 29

If you have an increase in renal arterial pressure, what does this do to GFR?

Back 29

this increases PGC

in the equation GFR= Kf (PGC-PBC-OncoticGC)

so increase GFR

Front 30

what does decreasing afferent arteriolar resistance do to GFR?

Back 30

this increases PGC

in the equation GFR= Kf (PGC-PBC-OncoticGC)

so increase GFR

Front 31

what does efferent constriction do to GFR?

Back 31

this increases PGC

in the equation GFR= Kf (PGC-PBC-OncoticGC)

so increase GFR

Front 32

if you have obstruction of a tubule or increased intratubular pressure, what does this do to GFR?

Back 32

this increases PBC

in the equation GFR= Kf (PGC-PBC-OncoticGC)

so decrease GFR

Front 33

if you have an increase in systemic-plasma oncotic pressure what will this do to GFR?

Back 33

this increases OncoticGC

in the equation GFR= Kf (PGC-PBC-OncoticGC)

so decrease GFR

Front 34

decrease in renal plasma flow will do what to GFR?

Back 34

this causes an increase rise of oncotic GC

so in the equation GFR= Kf (PGC-PBC-OncoticGC)

so decrease GFR