fluid-electrolyte physiology Flashcards
4 ways to measure protein in urine
- single urine [prot]
- 24 hour clleciton
- single urine protein/cr ratio
- sinle urine albumin/Cr ratio
what is urine [prot}
amount of protein in urine/urine vol.
what is prob with measuring [prot.]
depends on dilution of urine
what is adv. of 24hr collection
not dependant on fluid levels
what is large amount of protenuria
> 3.5g per day
what is a backup measure to assess [prot.]
also measure Cr and see if theres is a difference in the ratio
what is path through the tubule
PCT>DLOH>ALOH>DCT>CCD>MCD
why is so much water filtered if need to reabsorb
need to filter out all the dirty garbage
how is Na taken out of tubule
Na/K ATPase take Na out of epithelium and this then diffiuses into epithelium from tubule
3 main functions of proximal tubule
- bulk reabsorb of Na (80%)
- reabsorb other filtered “desirables” (H2O, Cl, glucose)
- acid base balance (reabsorb HCO3-
how is glucose reabsorbed with Na?
- from tubule into epi cell via SGLT transported
2. from cell to cap. via GLUT2 transporter
how is urea reabsorbed
as small [urea] becomes greater because Na and H2O are being reabsorbed there created a [c] gradient and the urea is reabsorbed too
what is special about asc. LOH
water impermiable
what does ALOH do?
reabsorbed Na (10%)
how is Na reabsorbed in ALOH
- Na/K ATPase pull Na into cap
- Na,K,2Cl trasnporter pushes K back into tubule
- high [K] creates a potential that pushes other cations back into cap
what is consequence of ALOH action
low Na at end and so fluid is dilute
3 functions of DCT
- reabsorbes NaCl (5%)
- impermeable to water
- reabsorb Ca (via PTH)
3 functions of Cort col duct
- reabsorb Na (1-5%)
- secrete K and H
- reabsorb lots of H2O if ADH present
how is H2O reabsorbed in CCT
- Aldost. bind to cystolic receptor
- enters nucleus and transcription changes
- new proteins
- inserts NaC channel in tubule wall
- Na comes into cell
- -ve charge left behind in tubule
- push out K and H into tubule (urine) via charge
what does MCT do?
- water in if has ADH
2. small Na reabsorb
how does ADH work
- ADH binds to receptor on cell wall and uses cAMP messenger system to put aquaporin in tubule side of cell
- water comes into cell and into cap.
where is K absorbed
PCT - 65-70%
LOH - 30%
CCD - some can be excreted
where is Ca absorbed
PCT - 65%
LOH - 25-30%
DCT - 5-10%
what happens to glucose
- filtered by glom
2. reabsorbed by PCT
