Flashcards in Renal Facts Deck (55)
Large pressure drop between what arterioles?
afferent arterioles (100 (55mmHg)) and then at the Efferent arterioles (50(20mmHg).
Does glomerular capillary pressure remain constant?
yes it does about 55mgHg so it favors filtration
what will reduce renal K+ secretion?
Vomiting aka alkalosis (because hypokalemia induced by K+ moving intracelluarly to release H+ to help cellular pH)
what do thiazide diuretics do to the calcium levels?
Block NNCT (Na+Cl- cotransporter)--> increased activity of basolateral Na+/Ca2+ exchanger to compensate --> hypercalcemia
loop diuretics...how will it effect the fractional excretion of cations?
loop diuretics block NKCC2 channels at Thick ascending limb (tubule becomes much more negative and doesnt want these positive cations to get reabsorbed) remember before the positive charge was kicking these cations out.
this will decrease reabsorption of all cations (directly Na and K) but also Mg2+ and Ca2+ because of paracellular drag.
Mg2+ is effected most because majority of Mg2+ is reabsorbed in the thick ascending limb
therefore FE of Mg2+ will increase most because more will be excreted.
Glucose increases ATP which blocks ATP sensitive K channels causing depolarization leading to VG calcium channels to open, what happens next?
intracellular Ca2+ increases exocytosis of vesicles and therefore insulin release.
If a substance is freely filtered and has lower clearance than inulin it is what??
reabsorbed (because inulin in not reabsorbed or secreted)
Wha does aldosterone act on and where?
Mainly distal tubule of nephron (increases the number of K channels, Na channels and Na/K pump) creates Na gradient for Na and H2O reabsorption
ENac, ROMK, Na/K atpase and increases ATP
some action in skeletal muscle and some in colon (increase K secretion, favor Na reabsorption and favor water reabsorption
what happens if you block NKCC2 to the fractional excretion of Mg, Ca, Na? put them in order
Magnesium is most affected
What happens to the body if you have an H+ inhibitor?
what happens to the body during vomiting?
If you give a patient a carbonic acid inhibitor what happens?
loss of HCO3- (bicarb) more stays in the lumen and is excreted because CA is not able to convert H2O3 into H2O and C2O
does not have an effect on K
If a person is lost in the desert without food or water for 2 days, what happens to their plasma osmolarity, their ECW and how does the box shift?
Plasma Osmolarity --> Hyperosmotic volume (due to no proteins or water)
ECW will then shrink so hyperosmotic volume with contraction
ECW is the more concentration (Compared to ICW) so the water moves into the ECW
so therefore contraction
If a person is lost in the desert without food or water for 2 days what happens?
RAA system will be activated and therefore an increase in Angiotension II and ADH ( need to increase water channels for more H20 reabsorption).
Decrease in ECV as well
During maximum ADH secretion where is most of the water reabsorbed?
proximal tubule (remember that even though its acting on the distal tubule; 65% is still being reabsorbed in the proximal tubule)
if you have amino acids and glucose in your urine, then where is the problem?
but also if there could be too much glucose saturating the transporters, over the threshold.
what happens to the flow rate as you increase your sodium intake?
As you increase Na intake you increase your ECF and therefore increase ANP (need to get of this excess Na) --> constricting the efferent arterioles and decreasing Na in the collecting duct and therefore increasing Na excretion.
Sympathetic activity, osmotic pressure of capillary and RAA system are all decreased
what is autoregulation?
keeps GFR and RBF constant between 80-180mmHg
reduced renal blood flow
>180mmHg --> severe HTN and autoregulation stops
what are the two autoregulation responses?
Myogenic response --> increases arterial pressure and stretches SM in BV walls. so you get increased afferent arteriole contraction
opens calcium channels
Tubuloglomerular Feedback --> involves macula densa and vasoactive substances to constrict afferent/efferent arterioles.
what are the three main points in regards to counter current exchange?
ATP dependent solute transport
Increase in osmolality in medullary interstitium
slow tubular fluid flow ( allows for less reabsorption)
what are some basics of the counter current exchange?
In the thick portion of the ascending limb, Na and Cl are actively removed.
Na and Cl leave by diffusion in the thin ascending limb
H20 movement is from descending limb to equilibrate increasing interstitial concentrations
Filtrate is super concentrated by the bottom of the loop (because all your water has been reabsorbed and your solutes have been impermeable)
At the end of the counter current exchange what should happen?
equilibrate the collecting duct with the interstitium
If a patients creatinine is elevated then what goes up and what does that mean?
Inversely rated to GFR so there is a decrease in GFR
freely filtered and not usually reabsorbed, so if there is creatinine in the patients plasma then its not getting filtered and that means that the GFR is down
If there is a PTH secreting tumor then what happens?
Addisons Disease (primary hyperparathyroidism)
What are some features of central diabetes insipidus?
Serum ADH --> decreased
Plasma Osmolarity --> high (excretion of excess water)
Urine Osmolarity --> hyposmotic
Urine Flow rate --> high
what are some features of peripheral (nephrogenic) diabetes insipidius?
Serum ADH--> High (the receptors in the nephron have been damaged) does not respond to exogenous ADH
Plasma Osmolarity --> High (excretion of excess water)
Urine Osmolarity --> Hyposmotic
Urine Flow Rate--> High
If a patient comes in urinating often and you give her a dose of vasopressin, what happens?
Central Diabetes will respond to the exogenous ADH and therefore the urine becomes concentrated
however peripheral will not respond and the values will stay the same
If someone drinks a lot of water and proceeds to pee it out,what happens to their free water clearance??
what does hypervolemia mean?
too much fluid in the blood