Vasopressin & Desmopressin
- What part of the nephron do they act upon?
- What do they increase permeability to?
1.
Medullary segment of Collecting Duct
2.
Water and Urea
How does high altitude affect the following:
- Arteriole pH
- Renal H+ excretion
- Renal HCO3 excretion
- Increased pH
(due to hyperventillation –> decreased PCO2)
- Decreased H+ excretion
(to compensate for increased pH)
- Decreased HCO3- reabsorption
In the absence of ADH, where would tubular fluid:
A. Have the highest osmolarity
B. Have the lowest osmolarity
Highest osmolarity:
C - the junction between the ascending and descending limb
Lowest Osmolarity:
F - collecting duct
In the setting of ADH, where would tubular fluid:
- Have the highest osmolarity (2)
- . Have the lowest osmolarity
1 - Highest osmolarity:
C - the junction between the ascending and descending limb
F - the collecting duct
2. Lowest Osmolarity
E - Distal convoluted tubule
In which nephron segment would there be the lowest concentration of PAH?
(para-aminohippuric acid)
Bowman’s space (just before the PCT)
PAH gets secreted into the nephron by the PCT and is not reabsorbed by any portion of the nephron. Therefore Bowman’s space which is before the PCT will have the lowest
How are the following altered by constricting the efferent arteriole:
- GFR
- RPF (renal plasma flow)
- FF (filtration fraction)
- Increased GFR
- Decreased RPF
- Increased FF
(NOTE: FF = GFR/RPF)
How are the following altered by constricting the afferent arteriole:
- GFR
- RPF (renal plasma flow)
- FF (filtration fraction)
- decreased GFR
- Decreased RPF
- same FF
(NOTE: FF = GFR/RPF)
How are the following altered by dehydration
- GFR
- RPF (renal plasma flow)
- FF (filtration fraction)
- decreased GFR
- majorly decreased RPF
- increased FF
(NOTE: FF = GFR/RPF)
How are the following altered by constricting the Ureter
- GFR
- RPF (renal plasma flow)
- FF (filtration fraction)
- decreased GFR
- same RPF
- decreased FF
(NOTE: FF = GFR/RPF)
If the right kidney is stenotic, what changes are seen in the left kidney?
The left kidney will experience increased pressures so
- increased sodium excretion
- decreased renin secretion
Which cells of the kidney secrete erythropoietin?
Which cells of the kidney secrete renin?
Peritubular Interstitial cells
Juxtaglomerular Cells
Which part of the nephron is impermeable to water regardless of serum ADH?
D
The Ascending Limb of the Loop of Henle
What is the formular for:
- Renal Perfusion Flow (RPF)
- Renal Blood Flow (RBF)
1.
RPF = (UrinePAH)(urine flow rate) / (PlasmaPAH)
2.
RBF = (RPF) / (1 - hematocrit)
What is inulin used to estimate?
What is PAH used to estimate?
GFR
GFR = (Uinulin X Vurine) / Pinulin
RPF
RPF = (UPAH X Vurine) / PPAH
NOTE: U = [urine], V = urine flow rate, P = [plasma]
Where does the majority of water reabsorption occur?
Proximal Tubule
(regardless of a patients hydration status the majority of water is reabsorbed at the PCT due to the large amount of solutes reabsorbed here as well)
What are the normal values for the following:
- pH
- PaCO2
- [HCO3]
1.
Normal pH = 7.35-7.45
2.
Normal PaCO2 = 35-45 mm Hg
3.
Normal [HCO3] = 22-26 meq/L
