Week 10: Urinary Flashcards
I have blood inside the capillary, what’s that doing?
pushing out
I have particles inside capillaries, whats that doing?
sucking in
I have fluid outside capillary, whats that doing?
pushing in
I have particles outside, whats that doing?
sucking out
It’s the same thing as starling but the difference is?
all same pressures in the same direction but all we did is there is a capsule around it and draw it like it’s a knot and rather than a straight capillary like we do in systemic capillaries
whats gonna be different about this?
this system is not built to have filtration at one part of glomerulus and reabsorption at another part glomerulus.
what is it built for?
only allow filtration
how do we do that?
by having the glomerular capillary pressure higher than systemic capillary pressure
CHP in the glomerulus, instead of being 35, its?
60 mmHg
COP and IFOP is gonna be 0 because?
we’re not leaving the capillary/particles
a lot of the things that contribute to the osmotic concentration of blood (RBC, WBC, Platelets, plasma proteins) are too big to?
get filtered
- they’re not getting in the interstitial fluid space
, so the osmotic concentration of interstitial fluid is going to be higher or lower?
much lower than you expect in a systemic capillary
the COP is gonna be relatively high because?
we’re not reabsorbing
mostly what is leaving?
mostly water is leaving and a whole bunch or particles that are too big to get filtered.
the interstitial pressure (pressure in the capsilar space) is going to be higher but the whole thing is rigged to have?
the net filtration pressure throughout the glomerulus be positive
- if it gets to 0, we have a problem
the net filtration pressure is?
10 mmHg
- bc that’s gonna give us glomerular filtration rate (how much am i filtering collectively at all my glomeruli in a period of time)
glomerular filtration rate is?
directly proportional to net filtration pressure
net filtration pressure goes up the glomerular filtration rate should go up or down
up
net filtration pressure goes down, glomerular filtration rate goes? up or down
down
with a net filtration pressure of 10 mmHg, in a healthy person, what is the glomerular filtration rate?
180 liters a day
- 60x a normal plasma volume
what is the daily urine output?
a liter and a half a day
- 99% of what you filter gets reabsorbed
what problems would affect the capillary hydrostatic pressure in the glomeruli?
hemorrhage, dehydrated, and medication problems
that affects what?
whether or not your patients kidneys are working effectively or not
what’s gonna determine CHP in a glomerulus is?
how much blood you have in the glomerulus
anything that makes it easier for blood to get into glomerulus or harder for blood to get out is going to?
increase net filtration pressure which will increase glomerular filtration rate
anything that makes it harder for blood to get in or easier to get out is?
lower the amount of blood in glomerulus and lower glomerular filtration rate
i have an entrance to glomerulus which is the afferent arteriole, and i have an exit from glomerulus which is the efferent arteriole.
If i dilate my afferent arteriole, and this particular nephron, it makes it easier for?
blood to get into the glomerulus.
- it increases glomerular blood volume
what’s that gonna do to net filtration pressure?
increase it
- if net filtration pressure goes up, glomerular filtration rate goes up
if i leave my afferent arteriole alone in its normal resting state but i constrict my efferent arteriole, now it’s harder to?
let blood out and then bringing blood in at the same rate i have before that’s also gonna increase volume of blood in glomerulus and ultimately increase GFR
if i dilate efferent arteriole, its easier for?
blood to get out
if i constrict my afferent arteriole and make it harder for blood to get in,
it has the same affect
if i want to really want to screw things up, i can dilate my afferent arteriole and constrict efferent arteriole,
make a huge jump in glomerulus filtration rate
or i can constrict my afferent and dilate my efferent..
harder to get in and easier to get out and it will drop a lot
the sympathetic nervous system is going to?
adjust what’s going on with the afferent and efferent arteriole.
- there are gonna be some other things here that are going to be into play to help determine glomerular filtration rate
what if inward pressures equal outward pressures and NFP is 0?
nothing happens cuz NFP is 0
if you give a patient medication that doubles their mean arterial pressure, their GFR would not go up about?
15%
- why? your body autoregulates glomerular filtration rate. it is a way of protecting the size of filtration slits.
if you give patient medication that doubles their mean arterial pressure and the glomeruli have no defense mechanisms, what will happed?
im going to blow out their kidneys
we don’t need much protection against ?
effects of bp lowering too much
- it may kill you but it wont cause permanent damage to kidneys
- really high bp at the glomeruli will
what is the myogenic mechanism?
has to do with what’s going on in the afferent arteriole. if bp to this particular nephron goes up, it stretches smooth muscle which causes a reflex vasoconstriction. im protecting glomerulus from that big jump in bp, im not damaging filtration slits, im letting plasma proteins and RBC and stuf wind up in filtrate
this is something that is happening at each individual?
nephron
if you have 50 nephrons where bp is higher than it should be, theyll all?
stretch and vasoconstrict
if your other nephrons aren’t seeing that, theyre not going to?
respond as a group
- this is going to be evaluated one nephron at a time based on what the pressure is in the afferent arteriole and whether we’re stretching that smooth muscle
once we get to glomerulus, what are the 2 problems?
- there is no way to constrict it
- once it gets to glomerulus, we’re already doing damage
we have hormones that will affect GFR which include? RASS especially renin will be?
adjusted by bp
if bp is low, what happens to renin release?
it will go up
if bp is high and it happens to be coupled with high blood volume, then we get release of?
atrial natriuretic hormone
when you have too much blood volume, and that is causing the high bp, ANH will help to ?
increase my GFR so i can get rid of the excess fluid`
if bp is low, and renin secretion has gone up, renin will?
decrease my GFR so i lose less water
if we increase GFR, more filtrate is produced. most of that filtrate is water. so if i have a high blood volume and i need to get rid of more water, high blood volume stimulates ANH release, and the ANH will act as?
on a nephron to increase GFR. filter more, got more water in filtrate, and now i will leave it there and go out of the body.
when i have low bp at my nephron, renin release goes up. low blood pressure may be an indicatory of?
low blood volume
- not always but it might be
the renin, among the other things it does, is going to decrease GFR. less fluid goes into the filtrate meaning?
there’s less time of losing that fluid so if my bp problem was bc i have low blood volume, i dont want my blood volume to keep dropping, so im going to filter less and decrease the chance of losing ?? 1:29
if bp goes up, that is detected by the JG cells, what happens to renin release?
it will go down
if bp goes up bc blood volume goes up, you’re going to stretch the?
atria of heart and get ANH released into the blood.
not having as much renin, will help increase?
GFR
the hormone affects the?
GFR
we’re also going to have some sympathetic system innervation in our?
afferent arterioles
if patient is having baroreceptor response bc their bp is too low, what does that crank up?
your sympathetic nervous system
- HR goes up
- you’re vasoconstricting
- in systemic arterioles is also vasoconstricting
- and afferent arterioles 1:31 to decrease GFR