Phys: Vanders Ch 2

Front 1

Standard glomerular filtration rate?

Back 1

125ml

Front 2

What is the filtration fraction? (FF=)

Back 2

ratio of glomerular filtration rate/ renal plasma flow

GFR/RPF

Front 3

What is RBF determined by (2 things)

Back 3

mean pressure in the renal artery
contractile state of smooth muscle of the renal arterioles

Front 4

In what order does filtrate pass through the filtration barrier?

Back 4

1. glomerular capillary endothelial layer
2. basement membrane
3. slit diaphragms

Front 5

The filtration barrier is selective for what two factors?

Back 5

Size and charge

Front 6

Which are filtered to a greater extent, positive or negatively charged macromolecules? Why?

Back 6

Positively charge particles are filtered to a greater extent
-b/c the filtration barrier repels negatively charged macromolecules during filtration

Front 7

What does a high GFR mean?

Back 7

greater excretion of salt and water

Front 8

what determines the rate of filtration in any of the body's capillaries (3 things)

Back 8

hydraulic permeability of the capillaries, their surface area,and net filtration pressure (NFP)

Front 9

Rate of filtration=?

Back 9

Hydraulic permeability x surface area x NFP

surface area may be expressed as the filtration coefficient (Kf)

Front 10

NFP=?

Back 10

(PGC- pieGC) - (PBC-pieBC)

PGC= glomerular capillary hydrostatic pressure
pieBC=oncotic pressure of fluid in Bowman's Capsule
PBC=hydrostatic pressure in Bowman's Capsule
pieGC=oncotic pressure in glomerular capillaries

Front 11

GFR=?

Back 11

Kf (PGC-PBC-pieGC)

Front 12

what happens to glomeruli oncotic pressure (pieGC) as you move down the capillary? why?

Back 12

it will increase; because water is moving out of the vascular space leaving protein behind; this increases protein concentration and thus the oncotic pressure

Front 13

From beginning to end of the glomerular capillaries how does filtration change and why?

Back 13

It will decrease, due to the increased pieGC

that will decrease NFP and thus GFR

Front 14

what happens to GFR if Kf is increased?

Back 14

increase (due to increased glomerular surface area)

Front 15

what happens to GFR if PGC is increased? de

Back 15

increased: leads to increased GFR

Front 16

if you increase renal arterial pressure, what happens to PGC?

Back 16

it will increase

Front 17

decrease in afferent resistance does what to PGC?

Back 17

raise PGC

Front 18

if you increase resistance in the afferent arteriole what will this do to PGC? and GFR?

Back 18

decrease PGC
thus lowering GFR

Front 19

If you increase resistance in the efferent arteriole, what will happen to PGC? GFR?

Back 19

increase PGC
thus increasing GFR

Front 20

decrease in efferent resistance does what to PGC?

Back 20

lower PGC

Front 21

If you increase afferent resistance, what happens to RBF?

Back 21

decrease RBF

Front 22

if you increase efferent arteriole resistance what happens to RBF?

Back 22

decreases

Front 23

if you increase BOTH afferent and efferent arteriole resistance, what happens to PGC? RBF?

Back 23

PGC: stays the same
RBF: decreases

Front 24

what will increased pieGC do to GFR

Back 24

lower it

Front 25

what will low RPF do to pieGC and thus GFR?

Back 25

low RPF-->increase pieGC-->lower GFR

Front 26

what is the basic idea of autoregulation in the kidney?

Back 26

in order to preserve a healthy GFR (not too high or too low, which would cause damage) there are mechanisms in place to maintain GFR and RBF

Front 27

As mean arteriole pressure changes, how does the body react?

Back 27

it is counteracted by a rise in vascular resistance to try and offset the effect

Front 28

As BP increases, what happens to Renal blood Flow? how is this accomplished?

Back 28

for the most part it stays the same; due to autoregulatory response

Front 29

what is a myogenic response? what does this do to RBF and GFR?

Back 29

to keep RBF constant in the face of increasing BP, the vascular smooth muscle will relax; this helps keep changes in GFR small

Front 30

as the filtration rate increases in an individual nephron, what happnes to the amount of Na that escapes reabsorption in the proximal tubule and loop of Henley?

Back 30

increases

Front 31

high sodium flowing past the macula densa causes what?

Back 31

decrease in filtration rate

Front 32

how does the macula densa actually effect filtration rate?

Back 32

by sensing increased Na, it will cause the vasoconstriction of the afferent arteriole thus reducing PGC and therefore GFR

Front 33

19. After nephrectomy what dominates GFR?

Back 33

a. Decrease in afferent resistance
b. Get large increase in GFR in the remnant kidney due to a decrease in the R of the afferent arteriole

Front 34

c. With lower relative constrictions of the efferent arteriole, what dominates GFR?

Back 34

Increased PGC

meaning GFR is increased

Front 35

d. With higher constrictions of the efferent arteriole, what dominates GFR?

Back 35

With high constrictions RBF is significantly lowered, thus lowering GFR

Front 36

What are the 2 autoregulatory responses

Back 36

myogenic response, tubuloglomerular feedback

Front 37

What is tubuloglomerular feedback?

Back 37

1. Increases and decreases in GFR are refelccted as increases or decreases in NaCL sensed by the macula densa
2. Protects the glomerulous from huge fluctuations
3. Paracrines from macula densa scoot over to the afferent arteriole to constrict or dilate that vessel

basically the macula densa response

Front 38

27. What are the 2 key factors that modulate RBF and GFR and how?

Back 38

a. RAAS: Ang II constricts both afferent and efferent arterioles (efferent more than afferent)
b. SNS: constricts both afferent and efferent arterioles
c. Net effect: decrease in RPF with only a little or no change in GFR

Front 39

32. ANP causes?

Back 39

a. Vasodilates both afferent and efferent arterioles thus causes increase in both RBF and GFR also inhibits the secretion of rennin

Front 40

What effect do prostaglandins have in the kidney?

Back 40

a. Generally proteteive against excessive vasoconstrtriction (like what you might see with lots of SNS and ANGII)
b. They can help to maintain RBF and GFR when there is a high sympathetic outflow and lots of RAAS
c. So prostaglandins will vasodilate

Front 41

what effect does dopamine have

Back 41

vasodilation

Front 42

25. When you have a volume expansion, what is the body reflex?

Back 42

a. To lower SNS activity and lower RAAS

Front 43

21. What does SNS stimulation + angiotensin do?

Back 43

a. Both afferent and efferent resistances increase
i. The increase in afferent R will decrease PGC while increase in efferent R will increase PGC
1. This creates opposing effects on GFR that keeps GFR fairly constant in spite of a decrease in renal plasma flow
b. RBF decreases
c. Ang II has a preferential efferent effect