Renal and Acid-Base Physiology Flashcards
1
Q
2/3 of TBW
A
intracellular fluid
K, Mg, protein and organic phosphates
2
Q
1/3 of TBW
A
extracellular fluid
1/4 is plasma
3/4 is interstitial fluid
3
Q
Marker for TBW
A
tritiated H2O, D2O
4
Q
Marker for ECF
A
Sulfate, inulin, mannitol
5
Q
Marker for Plasma
A
Radioiodinated serum albumin (RISA), Evans Blue
6
Q
Interstitial Fluid marker
A
measured indirectly
ECF-plasma volume
7
Q
Marker for ICF
A
measured indirectly
TBW-ECF
8
Q
Infusion of isotonic NaCl - addition of isotonic fluid
A
isosmotic volume expansion
ECF volume increases but no change in osmolarity
9
Q
Diarrhea - loss of isotonic fluid
A
isosmotic volume contraction
ECF volume decreases no change in osmolaritiy
10
Q
Excessive NaCl intake - addition of NaCl
A
Hyperosmotic volume expansion
osmolarity of ECF increases and water shifts from ICF to ECF
ICF osmolarity increases until it equals that of ECF
11
Q
sweating, fever, diabetes insipidus
A
hyperosmotic volume contraction
decrease in ECF, ICF volume and increase ECF osmolarity
12
Q
SIADH
A
hyposmotic volume expansion
increase in ECF & ICF volume and decrease in ECF osmolarity
13
Q
Adrenal Insufficiency
A
hyposomotic volume contraction
decrease in ECF volume, increase in ICF volume, ECF osmolarity is decreased
14
Q
Clearance Equation
A
CL = (UV)/P
U is urine conc
V is urine vol/time
P is plasma conc
15
Q
Vasoconstriction of renal arterioles on RBF
A
RBF will decrease
16
Q
Low conc of Ang II
A
preferentially constricts efferent arterioles and increase GFR
17
Q
ACE-inhibitors on GFR
A
dilate efferent arterioles thus decreasing GFR
18
Q
Vasodilation of renal arterioles on RBF
A
increase in RBF, is produced by PGE2 and PGI2, bradykinin, NO and dopamine
19
Q
Macula Densa
A
increases renal artery pressure leads to increased delivery of fluid to macula densa
increased load causes constriction of nearby afferent arteriole, increasing resistance to maintain constant blood flow
20
Q
Measurement of renal plasma flow
A
clearance of PAH, it is filtered and secreted by renal tubules
21
Q
RPF equation
A
Cpah = (Upah*V)/Ppah
22
Q
Measurement of RBF
A
RBF = RPF/(1-Hb)
23
Q
Measurement of GFR
A
clearance of inulin
Cin = (Uin*V)/Pin
24
Q
BUN and serum [creatinine] increase
A
when GFR decreases
25
Filtration Fraction
FF = GFR/RPF
| normal is ~0.20
26
increases in FF causes
increase in protein conc of peritubular capillary blood
| increased reabsorption in proximal tubule
27
decreases in FF causes
decreases in protein conc of peritubular capillary blood
| decreased reabsorption in proximal tubule
28
GFR Starling eqtn
GFR = Kf[(Pgc-Pbs)-(OSMgc-OSMbs)
29
Constriction of Afferent Arteriole (sympathetic)
decrease GFR, decrease RPF, no change in FF
30
Constriction of Efferent Arteriole (angII)
increase GFR, decrease RPF, increase FF
31
increased plasma [protein]
decrease GFR, no change in RPF, decrease FF
32
Kidney Stone
decrease GFR, no change in RPF, decrease FF
33
Filtered Load
GFR * [plasma]
34
Excretion rate
V * [urine]
35
Reabsorption rate
Filtered Load - Excretion Rate
36
Secretion Rate
Excretion Rate - Filtered Load
37
Splay (on Tm for glucose)
excretion of glucose before glucose is fully saturated
| ususllay between 250 and 350
38
HA form predominates in which type of urine?
acidic urine
39
A- form predominates in which type of urine?
alkaline
40
How to excrete salicylate acid
increase excretion by alkalinizing the urine
41
compares the concentration of a substance in tubular fluid at any point along the nephron with the conc in plasma
Tubular Fluid/Plasma ratio
42
TF/P = 1
no reabsorption of substance or reabsorption of the substance is exactly proportional to the reabsorption of water
43
TF/P < 1
reabsorption of substance
44
TF/P > 1
secretion of substance
45
Reabsorbs 2/3 of 67% of filtered Na and H2O in nephron
Proximal Tubule
46
Isosmotic process in the renal tubules
in Proximal Tubules
47
Carbonic anhydrase inhibitor
diuretic that act in early PT by inhibiting the reabsorption of filtered HCO3-
48
Late Proximal tubules reabsorbs what
Sodium and Chloride
49
Reabsorbs 25% of filtered Na+
Thick Ascending Limb of Henle
50
inhibits Na-K-2Cl in TAL
loop diuretics like furosimide, ethacrynic acid and bumetanide
51
impermeable to water
Thick ascending limb of henle, early distal tubule
52
diluting segment
TAL, TF/P is <1
53
site of action of thiazide diuretics
Distal Convoluted tubules
54
Principal Cells
in late distal tubule and collecting duct
Aldosterone - reabsorb Na and H2O & secrete K
ADH - increases H2O permeability
55
K-sparing diuretics
spironolactone, triamterene, amiloride
56
alpha-intercalated cells
secrete H+ by H-ATPase, stimulated by aldosterone
| reabsorbs potasium by H/K-ATPase
57
Causes of Hyperkalemia
insulin deficiency, acidosis
digitalis
exercise
cell lysis
58
Causes of Hypokalemia
insulin, beta-agonists, alkalosis, hypo-osmolarity
59
Hyperaldosteronism
increases K secretion and causes hypokalemia
60
Hypoaldosteronism
decreases K secretion and causes hyperkalemia
61
Increases the urea permeability of the inner medullary collecting ducts
ADH
62
Low urine flow rate
greater urea reabsorption
63
high urine flow rate
greater urea excretion
64
Phosphate reabsorbed in the PT
85% via Na-Phos Cotransport
65
PTH
inhibits phsophate reabsorption in PT by activating adenylate cyclase
increased Calcium reabsorption by activating AC in distal tubule
66
Treatment of idiopathic hypercalciuria
Thiazide diuretics
67
TAL competition
Mg and Ca compete for reabsorption, hypercalcemia causes an increase in Mg excretion
hypermagnesemia causes an increase in Ca excretion
68
hyperosmotic urine
when ADH levels are high, water deprivation, hemorrhage, SIADH
69
maintenance of the corticopapillary osmotic gradient
Countercurrent exchange in the vasa recta
countercurrent mulitplication in the loop of Henle
ADH has a big part in reabsorption of NaCl and Urea to make the gradient
70
Impermeable to water
TAL, therefore NaCl will be reabsorbed making the urine dilute therefore TF/P <1.0
Early distal convoluted tubule as well
71
Late Distal Tubules and high ADH
ADH increases the H2O permeability of principal cells
| TF/P = 1.0
72
Collecting Ducts and high ADH
ADH increases the H2O permeability of principal cells
| TF/P >1.0
73
Renal Tubules without ADH
PT: TF/P = 1.0 (isosmotic)
| TAL, early DT, late DT, and CT: TF/P <1.0
74
Used to estimate the ability to concentrate or dilute urine
Free water Clearance
- no ADH: Ch2o is (+)
- yes ADH: Ch2o is (-)
75
Primary Polydipsia
decreased ADH, decreased serum Na, hyposmotic urine, High urine flow rate, positive free water clearance
76
Central Diabetes Insipidus
decreased ADH, increased serum Na, hyposmotic urine, High urine flow rate, positive free water clearance
77
Nephrogenic diabetes insipidus
increased ADH, increased serum Na, hypoosmotic urine, high urine flow rate, positive free water clearnace
78
Water Deprivation
increase ADH, high/normal serum Na, hyperosmotic urine, low uring flow, negative free water clearance
79
SIADH
really increased ADH, decreased Na because too much water reabsorption, hyperosmotic urine, low urine flow rate, negative free water clearance
80
Stimulates 1alpha-hydroxylase
PTH
81
secreted when hyperosmotic plasma and decreased blood volume
ADH
| increases H2O permeability in LDT and CD principal cells
82
released when there is a decreased in blood volume and an icnrease in plasma [K]
Aldosterone
83
Actions of Aldosterone
increase sodium reabsorption in DT principal cells
increase K secretion in DT principal cells
increase H+ secretion in DT alpha-intercalated cells
84
what is release with an increase in atrial pressure and its MoA
ANP, cGMP
| used to increase GFR, decrease Na reabsorption
85
MoA of AngII
increases Na/H-exchange and HCO3- reabsorption in proximal tubule
86
Volatile Acid
CO2
87
When are buffers most effective?
within 1pH unit of the pK of buffer
88
Most important extracellular buffer
HCO3-
89
Most important urinary buffer
Phosphate
90
Intracellular Buffers
Organic Phosphates & Proteins like Imidazole and alpha-amino groups and Hb
deoxyHb is better buffer than oxyHb
91
Henderson-Hasselbalch Eqtn
pH = pK + loh ([A-]/[HA])
92
Buffer is most effective in what part of a titration curve?
Linear portion
93
Primary reabsorption site for HCO3-
proximal tubule
94
pCO2 and HCO3-
increased pCO2 => increased rates of HCO3- reabsorption, basis for renal compensation for respiratory acidosis
decreased pCO2 => decreased rates of HCO3- reabsorption, renal compensation for respiratory alkalosis
95
ECF volume and HCO3-
ECF volume expansion results in decreased HCO3- reabsorption
| ECF volume contraction results in increased HCO3 reabsorption
96
Diffusion Trapping
H+ is secreted into lumen via H-ATPase and combines with NH3 to form NH4
97
NH3 and acidosis
in acidosis, adaptive increase in NH3 synthesis occurs thus increasing gradient for NH3 diffusion
98
Inhibits NH3 synthesis
Hyperkalemia
99
Kussmaul Breathing
respiratory compensation for metabolic acidosis
100
Serum Anion Gap
For metabolic Acidosis
[Na]-([Cl]+[HCO3])
normal is 12mEq/L
101
Hypoventilation
respiratory compensation for metabolic alkalosis
102
Decerase in respiratory rate and retention of CO2
Respiratory Acidosis
| increase in both H+ and HCO3-
103
Winter Formula
PCO2 = (1.5 x HCO3) + 8 ± 2
• If Measured < Expected = Respiratory Alkalosis
• If Measured > Expected = Respiratory Acidosis
104
Anion Gap with K+
= ([Na] + [K]) − ([Cl] + [HCO3])
105
Metabolic Acidosis increase anion gap
```
Increase Anion ( >12 ): MUDPILES
Methanol
Uremia
Diabetic Ketoacidosis
Paraldehyde
Iron, Isoniazide
Lactate
Ethylene Glycol
Salicylates, Starvation
```
106
Metabolic Acidosis non-gap
normal is between 5-12: Hypercholemic
GI Loss: diarhhea, Sx drain, Fistula, Cholestryamine
Renal Loss: Renal tubular acidosis
• Proximal RTA – Acetazolamide (Diuretic)
• Distal RTA – Inpaired H+ Secretion, Cannot Acidify Urine
107
Nasogastric suction
causes metabolic alkalosis
108
medical procedures that cayse metabolic alkalosis with chloride sensitivity
vomiting, NG suction, diuretics, LR, TPN, Blood
109
Metabolic Acidosis - pH, primary disturbance, compensatory response
decreased pH, decreased HCO3
| compen - decrease pCO2
110
Metabolic Alkalosis - pH, primary disturbance, compensatory response
increased pH, increased HCO3
| compen - increase pCO2
111
Respiratory Acidosis - pH, primary disturbance, compensatory response
decreased pH, increased pCO2
| compen - increase HCO3
112
Respiratory Alkalosis - pH, primary disturbance, compensatory response
increased pH, decreased pCO2
| Compen - decrease HCO3
113
Furosimide, ALbuterol, Na Polysterene Sulfonate
Cause Hypo-K
114
Spironolactone, ACEi, Ibuprofen
Cause Hyper-K
115
Grossest Food Ever?
Onions
