Lecture 11/22: Renal Physiology Cont'd Flashcards
Final- Hopefully end smh
Where can we reabsorb water in the nephron?
PCT
TAL
DCT
Collecting duct
What is the osmolarity of the diluting segment
100 mOsm/L
Osmo in the PCT should be ______ to the plasma filtered
about equal
What is the pathology for hyponatremia?
This is decreased plasma Na+ osmo
Decreased ADH levels –> decrease urea reabsorption at the collecting duct –> dilute renal ISF & decreased AQP2 channels in the apical cell wall –> ions still being reabsorbed but not water –> increased water excretion
Where would you see a decrease in plasma osmo of Na+, K+, & Cl+?
End of the TAL in the loop of henle
PAH is increased in the nephron _____x
528
just know that its freely filtered & heavily secreted
Where would you see a dip in plasma osmo of creatinine/inulin?
last part of the loop on henle
What does diuresis mean?
Di = 2
Taking out ions & water
Where is the fluid excreted from diuretics coming from? How is it divided?
Extracellular fluid
Plasma 20%
ISF 80%
Explain the breakdown of excretion of 1L from a diuretic
1L of ECF
ECF: Plasma = 1/5
ISF = 4/5
Therefore: 200cc of Plasma was excreted
800 cc of ISF was excreted
T/F: Diuretics increase the amount of fluids we lose each day
F
It maintains the initial amount that we first took the drug
If we want to take off more fluid we have to increase the dose
Why are diuretics better for long term BP management than vasodilators?
With long term vasodilation, the body will find a way to work around that
Ex) with the nervous system: If it cant get the job done with Epi/NE –> releases ADH/ANGII to go around vasodilator
How much is total body water?
TBW is 60% of body mass
How do you find the the amount of ICF?
2/3 of TBW
How do you find the amount of ECF?
1/3 of TBW
What is considered ECF?
ISF and plasma
How do you find the amount of plasma?
ECF x (1/4) - ECF (1/5)
How do you find the amount of ISF?
ECF minus plasma
What are the values for TBW, ICF, ECF, Plasma, and ISF in a 70kg person?
TBW = 42 LITERS
ICF = 28 L
ECF = 14 L
Plasma = 2.8 - 3.5 L (Going to use 3L)
ISF = 11 L
Describe the pathology for chronically high ANGII. What is the treatment for this?
If salt intake increase = BP increases & increased filtration in kidneys
Cant suppress ANGII system
Increased salt will also increase water & raise BP
THIS IS A SYSTEMIC PROBLEM
Tx: decrease salt & water intake
Describe the pathology for Angiotensin II blockade. What is the temporary treatment for this?
Difficulty reabsorping Na to keep BP normal –> decreases Aldo as well –> Decreases BP
Temporary Tx: Increase salt intake
What is the pathology for 1 kidney becoming stenotic? What is the Tx for this?
Bad Kidney: ↓RBF –> ↓Pressure at GC –> ↓GFR –> ↓Na/Cl at MD –> ↑Renin/ANGII release –> Increase GFR
Good Kidney: ↑Renin/ANGII release effects this kidney too
-↑Pressure at GC –> ↑GFR
-AA will try to constrict to combat but wont be able to fully compensate so pressure still high
Tx: ACE inhibitor (-pril)
ARBs (-sartan)
What are surgical options available for the treatment of Renal artery stenosis?
Renal stent
Nephrectomy
T/F: A taste bud is an electrically excitable cell
T
What channels are on a taste bud?
Na+
K+
Remember you have some K+ channels on cells than Na
Why does adding salt to food makes things taste better?
It makes the taste bud cell more excitable
Na+ binds to its receptor on the taste bud → ↑ its membrane permeability allowing Na+ to come into the cell increasing its mV → ↑ taste
What is salt substitute?
K+
What is the difference between Essential hypertension & salt-sensitive hypertension?
They’re both forms of essential HTN
-essential HTN: idiopathic
-Salt intake does not increase the BP
-salt-sensitive hypertension: overexpression of RAAS
-salt intake will increase the BP
Low Renin production <– hallmark sign
______ HTN is seen more commonly in African Americans and NOT African Africans
Salt-sensitive hypertension
What are predisposers of essential HTN?
-Genes <– primary
-diet
What is the Tx for salt-sensitive hypertension?
ACE inhibitors (-prils)
Maybe ARBs? (-sartans)
What are some renal antihypertensive drugs?
-Mannitol
-ARBs (-sartans)
-ACE inhibitors (-pril)
-K+ sparing
What compounds can act like an osmotic diuretic?
Excess glucose
Excess Vitamin C
What are some Tx for renal failure?
Na+ restriction (lots of Na+ pumps in nephron)
K+ restriction (K+ secreted alot)
Protein restrictions (broken down to amino acids)
All these things increase the work of nephrons
**There are way more but these were highlighted **
What are some problems you’ll see with kidney failure?
Think, why did my pt need dialysis?
Hypernatremia
hypervolemia
hyperkalemia
hypertension
acidosis
What is the effects on giving isotonic fluids on fluid compartments?
ECF: add volume
ICF: No change
What is the effects on giving hypotonic fluids on fluid compartments?
EFC: Adds volume; decreases osmo –> water goes into cell
ICF: Adds volume; decreases osmo –> water goes into cell
What is the effects on giving hypertonic fluids on fluid compartments?
EFC: Adds volume; increases osmo –> water pulled out of cell
ICF: decreases volume; increases osmo –> water pulled out of cell
What is normal plasma creatinine?
1mg/dL
How much creatinine is normally secreted?
0.15mg/min
What is the normal excretion rate of creatinine?
1.40mg/min
With creatinine, Excretion rate has to equal ________
production rate
Creatinine is a byproduct of _______
skeletal muscle metabolism
What is normal filtered load of creatinine?
1.25mg/min
What happens to creatinine production when we have a nephrectomy? Why does this happen?
Everytime we lose half our nephrons, plasma creatinine has to double
We are still producing the same amount of creatinine = 1.4mg/min.
-We lost 1/2 nephrons: We are now only excreting 0.7mg/min now
-The excess that we are producing is BUILDING UP IN THE PLASMA!!!!
-Once the normal plasma creatinine doubles, it will now equal the production rate (The old excretion rate)
Plasma concentration would have to continue to rise until excretion rate equals production rate
What is physiology hypertrophy of the kidney?
About a year after a nephrectomy your kidney will get big/stronger –> able to do more work –> increases GFR by 50%
This is only if the remaining kidney is healthy
