Renal Transport Of HCO3- And H+ And Acid-Base Disorders

26 cards

5/4/10 9 Am


 
  
Created May 6, 2010
by
laurnb22

 

 
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1
What is the normal pattern of acid-base balance?
 
CO2 + nonvolatile acids are the acids you haveHCO3 - is the base
CO2 is blown off by the...
2
What are the 3 systems that control plasma pH?
 
1. Lungs2. Kidneys3. Buffers
3
What is the role of a proton buffer?
 
To minimize changes in pH
4
What is the equation for acid dissociation/formation?
 
HA <----> H+ + A-
5
What is the equation for pH?
 
pH = - log [H+]
6
WHat is the equation for pK?
 
pK = - log [K]
7
What is the Henderson-Hasslebach equation?
 
pH = pKa + log ([A-])/[HA]
8
What is the most important buffer in the body?
 
serum bicarbonate
9
What are the 2 roles of the kidneys in acid-base balance?
 
1.  Secrete H+ to reabsorb almost all of the filtered HCO3-2.  Secrete daily net...
10
Net urinary acid excretion has 2 parts.  What are they?
 
1. H+ excretion requires binding of H+ to buffers (ex: phosphate, creatinine, urea) to produce...
11
What is the equation for net urinary acid excretion?
 
Net urinary acid excretion = titratable acids + ammonium - (excretion of filtered HCO3-)
12
Why does the excretion of filtered HCO3- have to be subtracted from acid excretion to get the...
 
Because the reabsorption of HCO3- requires the secretion of H+.  So if some of the HCO3-...
13
How is an acid challenge handled?
 
3 steps are involved:1. HCO3- and non-HCO3- buffers in the plasma neutralize most of the H+B-...
14
HCO3- reabsorption requires __________
 
H+ secretion (NOT excretion!)
15
Describe HCO3- reabsorption.
 
HCO3- is converted by a luminal membrane CA to CO2 + OH-, and secreted H+ combines with the...
16
Describe excretion as a titratable acid.
 
For every H+ that is secreted, a new HCO3- is produced (by the intracellular carbonic anhydrase)...
17
Where is NH4+ secreted in the nephron?
 
Proximal tubule
18
Where is NH4+ reabsorbed in the nephron?
 
TAL
19
Describe NH4+ reabsorption by the TAL.
 
Apical membrane = NH4+ channels, Na/2Cl/NH4 cotransporterNH4 is broken down into H+ and NH3...
20
Describe NH4+ recycling in the LoH.
 
NH4+ reabsorbed by the TAL is broken down into NH3 and H+ in the interstitium.1) NH3 diffuses...
21
Describe the role of urea and glutamine metabolism in acid/bases.
 
Proteins and amino acid breakdown produces nitrogenous waste, which has to be converted to...
22
What are the effects of respiratory acidosis on H+ secretion?
 
Respiratory acidosis (i.e. increased PCO2) increases H+ secretion by an unknown mechanism
23
What are the effects of metabolic acidosis on H+ secretion?
 
Metabolic acidosis increases H+ secretion by increasing HCO3- uptake and reducing HCO3- backleak.
24
What are the effects of chronic metabolic acidosis on H+ secretion?
 
stimulates H+ secretion by increasing the activities of transporters and NH3 synthesis.
25
Name the 5 factors that increase HCO3- reabsorption
 
1. Respiratory acidosis (increased PCO2)2. Metabolic acidosis (decreased HCO3-)3. Hypokalemia 4....
26
Why does hypokalemia increase HCO3- reabsorption?
 
H/K pump on the a-intercalated cell, which is responsible for increasing K+ reabsorption.  Pumps...


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