Test 2: Wk7: 6 Water Balance - Puri Flashcards
— and — consumption decide solute excretion
salt and protein
— controls water excretion
hydration
if free water clearance is negative the kidney is
conserving water
CH2O =
CH2O = V (1 - (Uosm / Posm)
max and min free water clearance
1200 mOm/L
50 mOm/L
function of the countercurrent mechanism
create urine with an osmolarity different from serum osmolarity
countercurrent mechanism conserve water
generates urine osmolarity greater than plasma
countercurrent mechanism excrete water
urine osmolarity less than plasma
concentrated urine is produced when — is present in the plasma
ADH
In the absence of — a dilute urine is produced.
ADH
— is impermeable to solutes, but freely permeable to water.
The descending limb
— reabsorbs large quantities of NaCl & is impermeable to water.
The ascending limb
Reabsorption of NaCl without water creates a
dilute urine
— is called the “diluting segment”
The thick ascending limb
The interstitial around Henle’s loop provides the ΔOsm for
water to cross compartments
The medullary interstitium in the juxtaglomerular nephrons is —, with — increasing towards the hairpin loop
hypertonic; tonicity
— & — are required for renal water conservation
Hypertonic medullary interstitium and ADH
Medullary Hypertonicity does what
draws water out
ADH Provides
water permeability
Urine is progressively diluted by the —, —, and — regardless of the state of hydration
tALH, TAL, DCT—
urine at the end of the proximal tubule is always
isotonic
— and — are impermeable to water
tALH and TAL
Medullary Hypertonicity is Made By (3)
- Thin ascending limb—passive transport
2.Thick ascending limb—NKCC2
3.Collecting duct—urea transport by UTA1
—stimulated by ADH
Urine osmolality — and then —
along the nephron
rises; falls
Na transport in TAL
active
The Presence of Urea draws water out of the —, concentrating urine with NaCl.
tDLH
urea recycling
Urea that diffuses out of the MCD re-enters
the tubules in the thin limbs
ADH and urea
ADH responsible for removing urea
if free water clearance is negative then Na excretion > < =water excretion
>
If urinary osmolality is greater than
plasma—free water clearance is said to be
negative
If urinary osmolality is less than plasma —free water clearance is said to be
positve
ADH (AVP) binds to, and activates, —on the — of the nephrons and increases —
This leads to
V2 receptor; collecting ducts; cAMP
recycling of AQP2 & UT-A1 to
the luminal membrane
Through V1 receptor AVP induces
vasoconstriction and platelet aggregation