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302 Cards in this Set

  • Front
  • Back
1. In most conditions of acid or base loads,
nearly all of the bicarbonate is reabsorbed in
which tubular segment?
proximal tubules
2. Secretion of bicarbonate occurs in which
tubular segment?
collecting tubules
3. secretion of K+ occurs in which tubular
segment?
collecting tubules
4. When the dietary load of potassium is high,
A. potassium secretion occurs along the length of the renal tubule
B. reabsorption occurs in the proximal tubule, but secretion occurs in the collecting tubule
C. reabsorption rate of potassium increases in the proximal tubule
D. the filtered load of potassium decreases
E. rate of the basolateral Na+/K+ ATPase decreases
B. reabsorption occurs in the proximal tubule, but secretion occurs in the collecting tubule
The primary change in renal handling of potassium with diet occurs at the collecting tubules, which either to?
reabsorb potassium (alpha intercalated cells, collecting tubules)

or

secrete potassium (principal cells, collecting tubules).
The primary change in renal handling of potassium with diet occurs at the collecting tubules, which could reabsorb potassium from what cells and where?
alpha intercalated cells, collecting tubules
The primary change in renal handling of potassium with diet occurs at the collecting tubules, which could secrete potassium from what cells and where?
principal cells, collecting tubules
The filtered load would ________ with an increased
plasma [K+].
Increase
increasing the plasma concentration of any filtered solute will?
Increase the filtered load
Increasing [K+] of the dietary load will increase the rate of?
the Na+/K+ ATPase,

which is an important buffering response to the increase K+ load.
Increasing [K+] of the dietary load will increase the rate of the Na+/K+ ATPase, which is an important buffering response for
the increase K+ load.
5. The hormone that is secreted directly in response to plasma[K+] is
A. renin
B. angiotensin II
C. aldosterone
D. ANP
E. vasopressin
C. aldosterone.

The key to this question is “directly in response to”.
The cells of the adrenal cortex secrete more _______ when the plasma[K+] increase
.Aldosterone
The cells of the adrenal cortex secrete more aldosterone when?
the plasma[K+] increase.
The cells of the ________ secrete more aldosterone when the plasma[K+] increase.
adrenal cortex
6. Conditions that increase the flow rate through the renal tubules (such as osmotic diuresis) can
produce hypokalemia because

A. Na+ reabsorption in the proximal tubules is increased
B. the rate of the apical Na+/K+ ATPase increases with increased flow rate
C. increased flow in tubules increases the gradient for K+ transport
D. K+ reabsorption increased with increased flow
E. all of the above
C. increased flow in tubules increases the gradient for K+ transport
The increased flow such as osmotic diuresis helps maintain a favorable gradient for K+ secretion by?
continuously washing away the secreted K+.
The Na+/K+ ATPase is always on the _____ membrane.
Basal
The rate of this pump will increase with extracellular (plasma) K+.
Na+/K+ ATPase
Increased K+ reabsorption would lead to an increased in?
plasma[K+]
7. The K+ secreting principal cells
A. are also a primary site of K+ reabsorption under conditions of low K+
B. do not have a basolateral Na+/K+ ATPase
C. typically have a low intracellular conc. of K+
D. secrete K+ primarily via paracellular transport
E. secrete K+ via an apical, secondary active transporter
E. secrete K+ via an apical, secondary active transporter
All of the tubular cells have a basolateral?
NA+/K+ ATPase.
This active transport sets up the high intracellular/low extracellular K+ gradient.
NA+/K+ ATPase.
Secretion simply requires linking K+ gradient to?
an apical transporter
The reabsorption of K+ in the collecting tubule occurs via what different cell type?
the alpha intercalated cell
8. A plasma protein exists in an acid (HX) or base (X-) form, depending on the pH of plasma and the pK of the protein. At a plasma pH of 7.35, the ratio of base to acid is 100:1. The pK of this
protein is

A.-9.35
B.2.0
C.7.35
D.5.35
E. 9.35
D.5.35

pH= pK + log (base or unprotonated form)/ acid (protonated form)

pH- log (base or unprotonated form)/ acid (protonated form) = pK

since the ratio of unprotonated to protonated form is 100, and the log of 100=2

pK= 7.35 -2 = 5.35
9. Normally, the concentration of [Na+] is approximately _______ greater than that of [H+]
A. 103
B. 104
C. 105
D. 10
E. 106
E. 106
10. The pK of NH4+ is 9.0. If the pH of the tubular fluid is 6.0, then the ratio of NH3 to NH4+ in the tubular fluid must be

A. 1:3
B. 3:1
C. 3:2
D. 1:1000
E. 1000:1
D. 1:1000

Use the Henderson-Hasselbalch equation for this reaction:

pH= pK + log [NH3]/[NH4+]

pH = 6.0
pK= 9.0

the log of the ratio must be -3, which means that the concentration of NH4+ must be 1000 greater than the concentration of NH3.
The pH is determined by the ratio of?
the base to the acid.
11. An arterial blood plasma sample has a pH of 7.5, and a pCO2 of 20mmHg. The pK is 6.1. In
order to return the plasma pH to normal, the plasma [HCO3-} would have to be: (do this without
a calculator!)
A. 12 mmol/L
B. 48 mmol/L
C. 24 mmol/L
D. 60 mmol/L
E. 2.4 mmol/L
A. 12 mmol/L

As in problem 10, this requires that you apply the Henderson=Hasselbalch equation, and understand that the pH is determined by the ratio of the base to the acid.

pH= pK + log [HCO3-]/[CO2]

The pCO2 is half the normal value.

In order to restore the pH, we will need to make the HCO3- concentration half its normal value: 12mmol/ L

If you did use a calculator, you should have come up with the same answer, only you would need
to correct pCO2 to CO2 content

(Henry’s law)
[CO2]= 0.03 * pCO2, = .6mmol/L in this case

If normal pH=7.4, and pK=6.1

Then 7.4= 6.1 + log (hco3-)/ .6 Ln 1.3 =


log (HCO3-)/.6 Ln (1.3) = 20

[HCO3-]= 20 * .6 = 12mmol/L

It is much easier if you understand the importance of the ratio of base to acid
12. An example of an event that would impart a base load on the body is

A. eating a diet high in meat protein
B. increasing the secretion of bicarbonate by the pancreas
C. vomiting
D. holding your breath
C. vomiting
There are two ways to get a base load to the body?
adding bicarbonate to the plasma,
or
removing CO2.
Secreting bicarbonate is equivalent to?
adding acid to the plasma
Holding your breath is hypoventilation, which leads to?
an increased pCO2, and acidosis
13. The buffering system with the fastest complete response to an acid or base disturbance is

A. the respiratory ventilation rate
B. buffering within the extracellular fluid compartment
C. exchange of extracellular H+ for intracellular K+
D. change in the secretion of HCO3
E. change in the rate of renal formation of ammonium
B. buffering within the extracellular fluid compartment
The extracellular buffers are extremely?
fast acting.
The intracellular buffers are slower buffers because?
it takes more time for the H+ to be transported into the cells.
14. A molecule of HCO3- that is lost from the body via the GI tract

A. can combine with a H+ in the body to form CO2 and H2O
B. is equivalent to the addition of one fixed H+ to the body
C. is compensated for by renal secretion of one HCO3- molecule
D. all of the above.
B. is equivalent to the addition of one fixed H+ to the body
15. Carbonic anhydrase is found
A. in solution in the plasma
B. in solution in the tubular fluid
C. bound to apical membranes in proximal tubule cells
D. all of the above
C. bound to apical membranes in proximal tubule cells
Carbonic anhydrase is found?
bound to apical membrane of tubular cells and is also located within the cell.
carbonic anhydrase is bound to apical membrane of tubular cells and is also located within the cell, but within the cell it is not found just as?
a solute within the plasma, or within the tubular
fluids
Carbonic anhydrase is bound to apical membrane of tubular cells, and in that location, can do what within the lumen?
catalyze the formation of CO2 and H2O within the lumen.
16. Which of the following statements about bicarbonate is INCORRECT:

A. bicarbonate excretion increases during alkalosis
B. bicarbonate in the proximal tubule is reabsorbed primarily as H2CO3
C. bicarbonate reabsorption is dependent on carbonic anhydrase
D. most of the bicarbonate is reabsorbed by the proximal tubules
E. bicarbonate reabsorption in the proximal tubule depends on a Na+/H+ apical antiport.
B. bicarbonate in the proximal tubule is reabsorbed primarily as H2CO3
The molecules that enter the cell apically are?
CO2 and H20;
the molecule that exits the cell basolaterally is?
HCO3-.
17. During the response to an acid load
A. glutamine is metabolized to bicarbonate in the lumen of the collecting duct
molecule of H+
C. reabsorption of filtered bicarbonate is usually sufficient to compensate for the load
D. carbonic anhydrase catalyzes the formation of ammonium from glutamine
E. all of the above.
B. addition of one molecule of bicarbonate to plasma is equivalent to the secretion of one
18. In compensating for a daily acid load, the kidneys
A. excrete H+ bound to buffers
B. excrete excess H+ instead of reabsorbing HCO3-
C. excrete most of the acid as free [H+]
D. excrete H+ in exchange for glutamine primarily in the distal tubules
E. excrete H+ bound to glutamine
A. excrete H+ bound to buffers
With an acid load, any of the filtered HCO3- will be?
reabsorbed
With an acid load , any additional H+ will?
bind to various buffers in the tubular fluid. And
very little of it will remain as dissociated, free H+
The role of glutamine during an acid load is that it can be converted to?
intracellularly, to ammonium and bicarbonate.
The role of glutamine during an acid load is that it can be converted to intracellularly, to ammonium and bicarbonate. Then what happens?
The bicarbonate is transported into the plasma, and the ammonium transported into the tubular
fluid.
What is excretion?
what actually shows up in the urine
What is secretion?
the transport of ions across the membrane.
19. The beta intercalated cell of the collecting tubule
A. is the target for vasopressin in regulating water reabsorption
B. is the primary site of K+ secretion
C. is the primary site of K+ reabsorption in the collecting tubules
D. is the primary site of HCO3- secretion in the collecting tubules
E. is the primary site of HCO3- reabsorption in the collecting tubules
D. is the primary site of HCO3- secretion in the collecting tubules
20. Under conditions of an acid load, glutamine:

A. is the primary non-carbonic acid buffer in the plasma
B. is converted to NH3 and HCO3- within the cell
C. combines with HCO3- within the tubular fluid
D. dissociates into H+ and HCO3- by a reaction catalyzed by carbonic anhydrase
E. is synthesized by the liver at an increased rate
E. is synthesized by the liver at an increased rate
What is the reason that glutamine can play an increasing role with an increased H+ load
is synthesized by the liver at an increased rate and it can eventually contribute a bicarbonate ion to the plasma.
With an increased H+ load, Glutamine role is split into?
NH4+ (not NH3) and HCO3-.(not catalyzed by carbonic anhydrase)
Glutamine is important in dealing with an acid load
Because?
it can eventually contribute a bicarbonate ion to the plasma.
21. An individual filters
4500mmol HCO3- / day,
and excretes
30mmol/day of titratable acid,
50mmol/day of NH4+, and
10mmol/day of HCO3-.

How much HCO3- is added per day to the plasma?
A. 90mmol
B. 70 mmol
C. 50mmol
D. 30mmol
E. 4600 mmol
B. 70 mmol

(30mmol/day of titratable acid + 50mmol/day of NH4+) - 10mmol/day of HCO3-. = 70 mmol


the total HCO3- added to the plasma is the same as the total acid excreted


total acid excreted =

titratable acid + ammonium – excreted bicarbonate
excreting a bicarbonate ion is the same as?
adding a H+ to the plasma
The bicarbonate added to the plasma is ……….not the……..
the net, new bicarbonate,

reabsorption of the filtered bicarbonate.
22. An individual has a pulmonary disease, and now hyperventilates. Which of the following will
occur as a result?

A. the arterial pCO2 will be higher than normal
B. plasma [HCO3-] will be higher than normal
C. renal tubules will compensate by secreting more [HCO3-] than normal
D. renal tubules will compensate by secreting more NH4+ than normal
E. plasma buffers will maintain pH at the normal level
C. renal tubules will compensate by secreting more [HCO3-] than normal
An individual has a pulmonary disease, and now hyperventilates,hyperventilation will produce and a ______ pCO2
respiratory alkalosis,

lower than normal
An individual has a pulmonary disease, and now hyperventilates, the low pCO2 from respiratory alkalosis, will result of mass action on the plasma buffers, the plasma[HCO3-] will?
decrease although slightly

The renal tubules compensate by further lowering the HCO3- by secreting more in the
tubules. This dercease in HCO3- will balance the decreased pCO2, and help restore the pH closer
to normal .
There are no simple acid-base disturbances that would produce?
a decrease in pCO2 and an increase in plasma [HCO3-].
The plasma buffers reduce the pH change, but cannot?
eliminate the pH change
23. An individual has respiratory acidosis. With renal compensation, you would expect to find
what difference, compared to the acute (non-compensated) situation?
A. plasma [HCO3-] will be much greater than normal
B. a pH will be greater than normal
C. the ventilatory rate will return to normal
D. pCO2 will be slightly lower than normal
E. plasma [HCO3-} will be slightly lower than normal
A. plasma [HCO3-] will be much greater than normal
23. A. Respiratory acidosis is?

=
an increased pCO2 caused by hypoventilation.
An individual has respiratory acidosis. With renal compensation, The ventilatory rate would only change if?
the underlying condition were changed and is not directly tied to renal compensation.
During respiratory acidosis, there is an increase in pCO2. In the acute phase, there will be a slight increase in?
HCO3-, but the renal
system will increase this further.
An individual has respiratory acidosis. With renal compensation, How could this be balanced?
The increased HCO3- will help balance the increased CO2, and return the pH to normal
24. Which of the following would be the plasma values found in an individual with respiratory alkalosis with renal compensation?

pH
PaCO2 (mmHg)
[HCO3−] (mM)

A. 7.18 60 25
B. 7.33 60 32
C. 7.53 50 30
D. 7.49 30 18
E. 7.62 20 26
D. 7.49 30 18

pH 7.49

PaCO2 (mmHg) 30

[HCO3−] (mM) 18


Begin with the pH.

Alkalosis means that the pH is greater than normal, eliminating A and B.

Respiratory alkalosis is produced by a decreased pCO2, produced by hyperventilation.
The pCO2 must be less than normal, eliminating C.

you should expect that any compensation to a change in pCO2 should be a change in bicarbonate, and that change should occur in the same direction, in this case a decrease.
pH 7.53
PaCO2 – 50 (mmHg)
[HCO3−] – 30 (mM)

Note that the values are consistent with?
a metabolic alkalosis.
Alkalosis means that the pH is?
greater than normal,
Respiratory alkalosis is produced by?
a decreased pCO2, produced by hyperventilation.
you should expect that any compensation to a change in pCO2 should be a change in _____________ , and that change should occur in ….
bicarbonate
the same direction
25. What is the minimum amount of information you need in order to distinguish a metabolic from a respiratory acid/base disturbance?

A. pH
B. pH and pCO2
C. pH, pCO2 and plasma[HCO3-]
D. pH, pCO2, plasma[CHO3-] and net urine acid excretion rate
E. pH, pCO2, plasma[CHO3-], net urine acid excretion rate and urine pH
B. pH and pCO2
By itself, the pH will tell you ..... but .....
if it is an acidosis or alkalosis, not the cause.
Knowing the CO2 will help you distinguish ________ disturbance
the cause whether metabolic or respiratory
If it were respiratory acidosis, then the pCO2 would be _____________ – as the cause of the disturbance.
higher than normal
If it were metabolic acidosis, then the respiratory system would compensate for the
decrease HCO3- by?
decreasing the pCO2 (hyperventilating).
26. An elderly man comes to the clinic after 3 days of recurrent vomiting, and has the following
arterial blood values:

pH=7.5

pCO2= 55mmHg

[HCO3-] = 40mmol/L

Which of the following is your tentative diagnosis?
A. chronic respiratory alkalosis
B. Metabolic alkalosis with respiratory compensation
C. Acute respiratory acidosis with no renal compensation
D. Metabolic acidosis with respiratory compensation
E. Acute respiratory alkalosis with no renal compensation
B. Metabolic alkalosis with respiratory compensation

Begin with the pH.

A pH of 7.50 is higher than normal, so this is some type of alkalosis.

The pCO2 is higher than normal, so the respiratory rate is not the cause of the alkalosis, it is a
compensation for the alkalosis.

Note that the bicarbonate level is also above normal. The high bicarbonate is the cause of this disturbance.

The renal system will help restore the pH be secreting more bicarbonate.

As the bicarbonate falls, the respiratory system will follow.
27. For an individual with metabolic acidosis,

A. plasma buffers will raise the pH slightly above normal
B. ventilatory rate will increase
C. renal compensation will occur prior to the ventilatory rate
D. renal compensation will secrete more HCO3- in the urine
E ventilatory rate will stay the same as renal compensation occurs.
B. ventilatory rate will increase

By mass action, the plasma HCO3- will drop as the acid increased due to this metabolic
problem.

The buffers mitigate the pH change, but there will still be a decrease in pH, not an increase.

The respiratory system will compensate first (C), and will do so by hyperventilating,
thereby decreasing pCO2

The kidney will secrete less bicarbonate, not more, and will further excrete H+, and make new plasma bicarbonate

Ventilatory rate changes with the pH.

As the renal compensation brings the pH closer to normal, the ventilatory rate will adjust to the new pH
What are normal:
Arterial plasma -
pH Plasma [HCO3-] - mmol/L
pCO2 - mmHg
Arterial plasma pH – 7.35 – 7.43
Plasma [HCO3-] - 24 mmol/L
pCO2 – 40 mmHg
pH = ?
-log[H+]
Most enzymes and proteins normally function over a narrow range of pH, therefore regulating pH is?
critical.
Most enzymes and proteins normally function over a narrow range of pH, therefore regulating pH is critical. Example
Production of ATP

Metabolism of free fatty acids

Synthesis of cell membranes

Acetylcholine binding to Ach receptor
What pH is incompatible with life?
Less than 6.8 and Greater than 7.8
decreasing pH is ___ [H+]
increasing
increasing pH is ___ [H+]
decreasing
pH depends on?
temperature
PCO2
Plasma
Plasma[protein]
[strong base cations]-
[strong acid anions]
strong ion difference
pH depends temperature how?
increased temp~~> Increased [H+]
pH depends PCO2 how?
increased PCO2 ~~> increased [H+]
pH depends on strong ion difference how?
increased SID ~~> Decreased [H+]
Normal [H+] = 40nmol
TBW = 42L

total body H+ = ?
TBW * Normal [H+]

42L * 40nmol/L = 1.6 μmol
typical dietary process expels ____ CO2 in exhaling
& ____ non carbonic (non volatile) acid
13mol
40-80 mmol
Buffer- + H+ <~~~> HBuffer

Which is the weak base?

Which is the weak acid?
W.B ~~ Buffer
W.A ~~ H+
pH can vary btwn 4.4 to 7.4 but never gets to 4.4 because of?
Buffers
Buffer is?
“base” form,
because it results in a decreased [H+] of that solution
H buffer is?
“acid” form,
because results in a increased [H+] of that solution
Mass Action:
** Buffer- + H+ <~~> HBuffer **
rate of the reaction is proportional to?
the concentration of the reactants (esp. H+)
Mass Action:
** Buffer- + H+ <~~> HBuffer **

an increase in H+ drives reaction to the?
Right

** Buffer- + H+ <~~~ HBuffer **
Mass Action:
** Buffer- + H+ <~~> HBuffer **

an decrease in H+ drives reaction to the?
Left

** Buffer- + H+ ~~~> HBuffer **
Mass Action:
** Buffer- + H+ ~~> HBuffer **

in H+, what drives reaction to the Right?
Increase in H+
Mass Action:
** Buffer- + H+ <~~ HBuffer **

in H+, what drives reaction to the Leftt?
Decrease in H+
Buffers do what?
minimize the pH change (change in free concentration of H+) but do not remove acid or base
Resulting pH w/ buffer = formula
pK + log [base]/[acid]
(Henderson-Hasselbalch equation)
Buffering capacity of the body is huge, but over the long term, buffers have?
to be restored
Buffering capacity of the body is huge. Why?
A lot of buffers (and many pKa are close to their pH)
Disease processes can tax buffering capacity, placing additional requirement for?
restoring buffers
What can tax buffering capacity, placing additional requirement for restoring buffers
Disease processes
What are the sources of acids and bases?
1. Carbonic Acid (Volatile acid)

2. Non-carbonic (non-volatile) acid

3. GI secretions
What is this equation?

CO2* + H2O <~>H2CO3<~>H+* + HCO3-
* catalyzed by carbonic anhydrase
Carbonic Acid (Volatile acid)
What two components are catalyzed by carbonic anhydrase?
CO2 + H2O <~>H2CO3<~>H+ + HCO3-
CO2 and H+ of the formula:

CO2* + H2O <~>H2CO3<~>H+* + HCO3-
* catalyzed by carbonic anhydrase
Carbonic Acid (Volatile acid) generates how many moles of CO2 a day and how is it expelled?
13 moles of CO2
Exhaled
Carbonic anhydrase is not found in plasma (ECF), but is found in?
RBCs and numerous other tissues including:

renal tubular cells, pulmonary tissue, CNS, and as membrane bound forms in muscle and other
tissues.)
What is the source of Non-carbonic (non-volatile) acid?
Proteins: oxidative metabolism can result in the addition of acid, or of base, depending on the type of
protein.
Oxidative metabolism of Non-carbonic (non-volatile) acid can result in depending on the type of protein?
the addition of acid, or of base
Average American diet of high protein (mainly meat) produces a net acid of ____ mM/day
50-100 mM/day
What are the special elements of Non-carbonic (non-volatile) acid?
H2SO4, H2PO4
Anaerobic metabolism of carbohydrate and fat produces _______ which can be a significant addition of Non-carbonic (non-volatile) acid in some pathological conditions.
lactate,
Who produces ketones, which can be a significant addition of Non-carbonic (non-volatile) acid in some pathological conditions.
diabetics
Stomach acid secretion is balanced by?
small intestine base, but vomiting or diarrhea results in an acid or base deficit, respectively.
Stomach acid secretion is balanced by small intestine base, but what results in an acid or base deficit, respectively.
vomiting or diarrhea
Bicarbonate and base equivalents (organic anions) that are normally lost in the stool contribute an?
equimolar quantity of non-carbonic acid being left behind.
In GI secretions, every mole of base lost in the stool, one mole of acid is?
retained by the ECF
Acids and bases must balance. Transient changes in acids or bases are compensated so that?
acids and bases return to balance, even if it is at a higher or lower concentration
What is the response to acid or base load?
1.Chemical buffers
2. Respiratory compensation
3. Renal compensation
What are the three types of buffers in response to acid or base load?
Plasma bicarbonate/CO2
Protein buffers
Phosphate buffers
Formula for Plasma bicarbonate/CO2 is
(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O
Formula for Plasma bicarbonate/CO2 is:

(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O

If you add acid to this equation what happens?
Increase CO2, decrease HCO3-
Goes right

(H+) + HCO3- ~> H2CO3 ~> CO2 + H2O
What does Plasma bicarbonate/CO2 do and what is it responsible for?
Major buffer

• Responsible for >75% of plasma buffering capacity for protons from non-carbonic acids

• does not buffer protons from carbonic acid sources
Formula for Plasma bicarbonate/CO2

(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O

If you remove H+ to this equation what happens?
Decrease CO2, Increase HCO3-
Goes Left


(H+) + HCO3- <~ H2CO3 <~ CO2 + H2O
What is this equation?

CO2* + H2O <~>H2CO3<~>H+* + HCO3-
* catalyzed by carbonic anhydrase
Carbonic Acid (Volatile acid)
What two components are catalyzed by carbonic anhydrase?
CO2 + H2O <~>H2CO3<~>H+ + HCO3-
CO2 and H+ of the formula:

CO2* + H2O <~>H2CO3<~>H+* + HCO3-
* catalyzed by carbonic anhydrase
Carbonic Acid (Volatile acid) generates how many moles of CO2 a day and how is it expelled?
13 moles of CO2
Exhaled
Carbonic anhydrase is not found in plasma (ECF), but is found in?
RBCs and numerous other tissues including:

renal tubular cells, pulmonary tissue, CNS, and as membrane bound forms in muscle and other
tissues.)
What is the source of Non-carbonic (non-volatile) acid?
Proteins: oxidative metabolism can result in the addition of acid, or of base, depending on the type of
protein.
Oxidative metabolism of Non-carbonic (non-volatile) acid can result in depending on the type of protein?
the addition of acid, or of base
Average American diet of high protein (mainly meat) produces a net acid of ____ mM/day
50-100 mM/day
What are the special elements of Non-carbonic (non-volatile) acid?
H2SO4, H2PO4
Anaerobic metabolism of carbohydrate and fat produces _______ which can be a significant addition of Non-carbonic (non-volatile) acid in some pathological conditions.
lactate,
Who produces ketones, which can be a significant addition of Non-carbonic (non-volatile) acid in some pathological conditions.
diabetics
Stomach acid secretion is balanced by?
small intestine base, but vomiting or diarrhea results in an acid or base deficit, respectively.
Stomach acid secretion is balanced by small intestine base, but what results in an acid or base deficit, respectively.
vomiting or diarrhea
Bicarbonate and base equivalents (organic anions) that are normally lost in the stool contribute an?
equimolar quantity of non-carbonic acid being left behind.
In GI secretions, every mole of base lost in the stool, one mole of acid is?
retained by the ECF
Acids and bases must balance. Transient changes in acids or bases are compensated so that?
acids and bases return to balance, even if it is at a higher or lower concentration
What is the response to acid or base load?
1.Chemical buffers
2. Respiratory compensation
3. Renal compensation
What are the three types of buffers in response to acid or base load?
Plasma bicarbonate/CO2
Protein buffers
Phosphate buffers
Formula for Plasma bicarbonate/CO2 is
(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O
Formula for Plasma bicarbonate/CO2

(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O

If you add acid to this equation what happens?
Increase CO2, decrease HCO3-
Goes right

(H+) + HCO3- ~> H2CO3 ~> CO2 + H2O
Formula for Plasma bicarbonate/CO2

(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O

If you remove H+ to this equation what happens?
Decrease CO2, Increase HCO3-
Goes Left

(H+) + HCO3- <~ H2CO3 <~ CO2 + H2O
What does Plasma bicarbonate/CO2 do and what is it responsible for?
Major buffer

• Responsible for >75% of plasma buffering capacity for protons from non-carbonic acids

• does not buffer protons from carbonic acid sources
Formula for calculating pH containing dissolved CO2 (Plasma bicarbonate/CO2)
pH= pK + log[HCO3-]/(.03*pCO2)

Henry’s Law (.03*pCO2) converts the pCO2 to the molar content of dissolved CO2)
What restores the HCO3- in plasma bicarb. / CO2?
Renal function
What are composed as Protein buffers?
Hemoglobin in red blood cells, albumin in plasma, intracellular proteins
Hemoglobin buffer equation:
(H+) + Hb- <~> H*Hb
With Protein buffers, When H+ enters the cells, often it is balanced by?
the exit of Na+ or K+
Phosphate buffers are both?
organic and inorganic elements
The two equations of Phosphate buffers
(H+) + Org*HPO4- <~> Org*H2PO4-

(H+) + HPO4- <~> H2PO4-
In Phosphate buffers, buffers protons are from?
both carbonic and non-carbonic acid sources
Respiratory compensation is responsible for?
Regulating PCO2

(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O
How does Respiratory compensation Regulate PCO2?
• rapid response, although slower than chemical buffering systems
• bicarbonate _ CO2 in RBCs in the lung capillary
Respiratory compensation formula:
(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O
Ventilation rate changes in order to increase or decrease CO2 in?
Respiratory compensation in Regulating PCO2
In respiratory compensation in Regulating PCO2, What changes in order to increase or decrease CO2?
Ventilation rate changes
A decrease in pH will cause ________ and will ___________ ventilation and decreases _____
Acidosis
Increase ventilation
CO2
A increase in pH will cause ________ and will ___________ ventilation and will increase ________
Alkalosis
Decrease ventilation
pCO2
Alkalosis is an _______ in H+
decrease
Acidosis is an ________ in H+
increase
Acidosis will move the following rxn which way?

(H+) + HCO3- <~> H2CO3 <~> CO2 + H2O
to the left

(H+) + HCO3- <~ H2CO3 <~ CO2 + H2O
How does Renal compensation affect acid/base balance?
Long term regulation by altering HCO3- concentration – restoring buffering capacity

• excrete bicarbonate in urine (equivalent to increasing H+ to the plasma)

• secrete HCO3- into plasma (equivalent to removing a H+ ion from the plasma)
How does Renal compensation excrete to restore buffering capacity?
• excrete bicarbonate in urine (equivalent to increasing H+ to the plasma)
How does Renal compensation secrete to restore buffering capacity?
• secrete HCO3- into plasma (equivalent to removing a H+ ion from the plasma)
Although buffers of renal compensation mitigate the pH changes due to?
an acid or base load, acid base balance means that the buffers must be restored, and any excess acid or base must also be excreted.
acid base balance means that the buffers must be?
restored, and any excess acid or base must also be excreted
Typical individual: generates about_____ mmol CO2/day which is excreted by?
15,000 mmol CO2/day
Exhaled
Protein in avg. diet, generates ??? mmol non carbonic H+ /day
~ 40-80 mmol non carbonic H+ /day

H+ (from any source) + HCO3- (plasma) <~~> CO2 + H20
The added H+ in renal handling of acid/base does not change pH, but it does?
eliminate one bicarbonate as part of the buffering process.
The added ____ in renal handling of acid/base does not change pH, but it does eliminate _______________ as part of the buffering process.
H+
one bicarbonate
The added H+ in renal handling of acid/base does not change pH, but it does eliminate one bicarbonate as part of the buffering process.Acid/base balance requires?
that this bicarbonate be restored.
In regards to renal handling of acid/base, HCO3- is freely filtered at the kidney, so the kidney must do two things:
reabsorb the current filtered bicarbonate,

regenerate additional bicarbonate (excrete acid) to balance the load of nonvolatile acids
What are the normal values of HCO3- and pH of Plasma?
HCO3- = 24 mMol
pH = 7.4
What are the normal values of HCO3- and pH of ICF?
HCO3- = 10 mMol
pH = 7.2
What are the normal values of HCO3- and pH of Urine?
HCO3- = 0 mMol on typical diet
pH = 5.0 – 7.0
HCO3- is filtered how?
freely filtered
What is the magnitude of transport of HCO3

Filtered Load ~~ ? mmol/day
Excreted ~~ ? mmol/day
Reabsorbed~~ ? mmol/day
% filtered load reabsorbed ?%
Filtered Load ~~4500mmol/day
Excreted ~~2mmol/day
Reabsorbed~~4498mmol/day
% filtered load reabsorbed ~~ 99.9*
* depends on diet, and other conditions-
What part of the nephron reabsorbs the most HCO3-?
Proximal tubules
Distal regions of the Nephron does what with the HCO3-?
reabsorbs more HCO3- or secretes HCO3- as needed for acid/base balance
What part of the nephron reabsorbs more HCO3- or secretes HCO3- as needed for acid/base balance?
Distal regions
In the distal regions of the Nephron, Reabsorbing 1HCO3- is equivalent to?
Excreting one H+ in urine
In the distal regions of the Nephron, secreting 1 HCO3- is equivalent to
Add H+ to plasma
What is the formula for
[HCO3-] excreted?
[HCO3-] excreted =
[HCO3-] filtered + [HCO3-]secreted – [HCO3-] reabsorbed
The most reabsorption of filtered HCO3- happens in the?
Proximal tubule
What is filtered and/or secreted in the proximal tubule?
HCO3- is filtered; H+ is secreted
What are the steps of filtering HCO3- in the proximal tubule?
H+ combines with filtered HCO3- in lumen to form
H20 and CO2

Intracellular HCO3- enters interstitium

Carbonic anhydrase is present within the cell, and on
the luminal side of the plasma membrane

HCO3- is filtered into the lumen and HCO3- is released into the plasma
What are the Specific transporters in proximal tubule for H+ secretion?
H+ ATPase,

Na+/H+ antiport
What are the Specific transporters in proximal tubule for HCO3- reabsorption?
HCO3-/Cl- antiport,

HCO3-/Na+ symport
What percentage of filtered load is reabsorbed in proximal tubule?
75-90%
Where does homeostasis matter the most?
Collecting tubule
In the Collecting tubule, Alpha intercalated cells have an ……………………exchange
apical H+ ATPase

and a basolateral HCO3-/Cl- exchange
In the Collecting tubule, Except during __________, kidneys reabsorb all bicarbonate
Alkalosis
What completes reabsorption of all bicarb?
Kidneys
What is the result of transport of HCO3 in the collecting tubules?
no net increase in plasma bicarbonate

No net increase in H+ in tubules.
Formation of new bicarbonate to the plasma formula:

CO2 + H2O <~> H2CO3 <~> H+ (urine) + HCO3- (blood)

Where is new bicarbonate added to plasma formula:
CO2 + H2O <~> H2CO3 <~> **H+ (urine)** + **HCO3- (blood)**
With excess of H+ in plasma, the H+ will?
combine w/ non-bicarb. anions, usually (HPO4)2-
With excess of H+ in plasma, the H+ will combine w/ non-bicarb. anions, usually (HPO4)2- to form what equation:
(H+) + (HPO4)2- <~~> (H2PO4)-
Normally, H+ excretion associated with phosphate will balance about ____ mM/day of H+.
40 mM/day of H+
You can add ______ of HCO3- everyday in plasma
40 mM/day
On a typical American diet, additional mechanisms other than ..... are necessary to balance the acid load.
Formation of new bicarbonate
Formation of new bicarbonate results in?
Excreted H+ in tubular fluid
Formation of new bicarbonate will excrete ____ in urine and ______ in plasma
H+ (acid)
HCO3-
Formation of new bicarbonate if you still need more is?
ammonium secretion and production
Catabolism of amino acids produces two waste products that the kidney must excrete:
urea or glutamine

amino acids <~> (aerobic) 2NH4+ + 2HCO3- <~> (liver) urea or glutamine (+ CO2 & H2O)
What is Glutamine:
A waste product in the Proximal tubule
Glutamine is filtered by Kidney and taken up by tubular cells (particularly proximal tubule) from?
both lumen and peritubular capillaries.
Glutamine is filtered by the _______ and taken up by _______ from both lumen and peritubular capillaries.
Kidneys
tubular cells (particularly proximal tubule)

NH4+ <~~> NH3 + H+
Glutamine is metabolized to?
NH4+ and HCO3-
Glutamine increases with ______ pH
Decreased
Formation of new bicarbonate with ammonium secretion and production will result in
1 H+ in urine (apical) and 1 HCO3- added to plasma (baso)
A titratable acid is aka:
Formation of new bicarbonate
Glutamine During Formation of new bicarbonate what is actively secreted and by what exchange?
Small amount of NH4+ is actively secreted (NH4+/Na+ exchange)
What is the NH4+ and Secretion of H+ net effect in the Collecting duct:
The net effect is the formation of on new bicarbonate in the blood, and the loss of one H+ buffered by NH3
Summary of response to an acid load:
1. reabsorbed all filtered HCO3-
2. add new HCO3- & excrete H+ either with titratable acid and NH4+
What is base load?
High plasma HCO3-
What is the response to a base load?
Excretion of Bicarbonate
Normally, bicarbonate excretion is not part of the renal compensation to daily load, but it can be?
important in compensation for metabolic disturbances.
What happens in the Collecting tubule with base load?
Excretion
Beta intercalated cells have what type of exchangers?
apical bicarbonate/Chloride exchange,

basolateral H+/K+ exchange.
What is the net result in the Collecting tubule with base load?
The net result is excretion of one bicarbonate (gain of HCO3-)

and

An addition of one H+ into the plasma (loss of HCO3-)
What are the principle cells of collecting tubule cells?
Na+
K+
H2O
Na+ & K+ do what in the collecting tubule?
Reabsorb NA+ and Secrete K+ by Aldostrone
H2O does what in the collecting tubule?
Vasopressin regulation of water permeability
What are the Alpha intercalated cells of collecting tubule cells?
K+

H+
What does K+ of collecting tubule cells do?
K+ is reabsorbed
What does H+ of collecting tubule cells do?
H+ additional H+ secretion and HCO3- reabsorbed
What are the Beta intercalated cells of collecting tubule cells?
HCO3-
What does the HCO3 of collecting tubule cells do?
HCO3- secretion of HCO3-
Acid/base balance equation

acid load = acid loss
Non volatile acid + volatile (CO2) = excreted acid + exhaled CO2
What takes care of exhaled CO2 in this Acid/base balance equation
Resp. system takes care of CO2
Net acid excretion (G/E/L) net non volatile acid load
should equal
What is the “signal” for kidney regulation of acid base?

(H+) + HCO3- <~> H2CO3 <~>CO2 + H2O
CO2 may have specific effects
Net acid excretion in the urine (G/S/L) amount of HCO3- added to plasma
same as
Net acid Excretion formula:
(Titratable Acid + NH4) – (Any excreted HCO3-) =

New HCO3- has been added to plasma

[H+] is not included in this calculation:

pH of urine cannot go lower than about 4.5
Net acid Excretion formula:

(Titr. Acid + NH4)– (Any excreted HCO3-)

What is not included in this calculation:
[H+]
Find the net acid excretion for any individual with the following urine composition:
Titratable acid = 40mmol/day
NH4+ = 160mmole/day
HCO3- = 4mmol/day
pH (urine)= 4.6
(40 mmol/day + 160mmole/day) – 4 mMol/day
= 196 mMol/day

(this net acid excretion is higher than usual)
Renal compensation main function is?
changing the plasma bicarbonate
Net Acid excreted:

alkalosis – high HCO3- in plasma

What are the avg. values for:

titratable acid (mM/day)
Plus NH4+ excreted (mM/day)
minus HCO3- excreted
total (mM/day)
Urine pH
titratable acid ~ 0 mM/day

Plus NH4+ excreted ~ 0 mM/day

Minus HCO3- excreted
80 mM/day

total ~ -80 mM/day (lost from body)

Urine pH ~ 8.0
Net Acid excreted:

normal ~ avg. HCO3- in plasma

What are the avg. values for:

titratable acid (mM/day)
Plus NH4+ excreted (mM/day)
minus HCO3- excreted
total (mM/day)
Urine pH
titratable acid ~ 20 mM/day

Plus NH4+ excreted ~ 40 mM/day

Minus HCO3- excreted
1 mM/day

total ~ 59 mM/day (add to body)

Urine pH ~ 6.0
Net Acid excreted:

acidosis- Low HCO3- in plasma
What are the avg. values for:

titratable acid (mM/day)
Plus NH4+ excreted (mM/day)
minus HCO3- excreted
total (mM/day)
Urine pH
titratable acid ~ 40 mM/day

Plus NH4+ excreted ~ 160 mM/day

Minus HCO3- excreted
0 mM/day

total ~ 200 mM/day (added to body)

Urine pH ~ 4.6
We can excrete mMol/day of Acid
500 mMol/day
In acidosis conditions, a glutamine increase will do what to pH?
Decrease pH
Acidosis is elevated …. in plasma and pH is G/S/L normal
elevated H+ concentration

pH < normal
Alkalosis is elevated …. in plasma and pH is G/S/L normal
elevated HCO3- concentration

pH > normal
pH can tell you ……. But it doesn’t tell you…….
Elevated conc.

But not cause
Metabolic acid/base disorders result from a primary change in?
HCO3-
Respiratory acid/base disorders result from a primary disturbance in?
pCO2
What acid/base disorder results from a primary change in HCO3-
Metabolic disorders
What acid/base disorder results from a primary disturbance in pCO2?
Respiratory
What is Metabolic acidosis?
Too much H+ or lost of HCO3-
Example of Metabolic acidosis:
excess lactic acid production (exercise, or hypoxia)

or loss of bicarbonate (diarrhea, e.g.),
3 types of Compensation of the Metabolic acidosis:
1. chemical buffering by plasma

2. Respiratory compensation:

3. Renal compensation
Chemical Compensation of Metabolic acidosis is
chemical buffering by plasma
Metabolic acidosis is ____ HCO3- and ____ pH
Decrease HCO3-
Increase pH
Respiratory Compensation of Metabolic acidosis,
Ventilatory rate changes with?
Decrease pH ~~> ventilation (hyperventilation ~~> and decreased pCO2
Renal compensation of Metabolic acidosis involved in?
Restore HCO3- to plasma and also excrete H+ in urine
What is the end result of Renal compensation of Metabolic acidosis?
lower than normal pH, pCO2, HCO3-
A 21 year old man has had severe diarrhea for several days, and has been brought to the clinic by his concerned roommate. The physicians at the clinic find the following results from lab tests:

Arterial plasma pH ~ 6.98

Plasma [HCO3-] ~ 3 mmol/L

pCO2 ~ 13 mmHg

pH ~ (G/S/L) ~ normal
HCO3- ~ (G/S/L) ~ normal
pCO2 ~ (G/S/L) ~ normal

Condition:
Problem:
Effect:
pH ~ very less than ~ normal
HCO3- ~ less than ~ normal
pCO2 ~ less than ~ normal

Condition: Metabolic Acidosis

Problem: HCO3+

Effect: pCO2 (Resp.) compensation)
What is Metabolic alkalosis?
Too much HCO3- or too little H+
Condition: Metabolic alkalosis

Problem:

Effect:
Problem: increase in HCO3+
Effect: increase in pCO2 (Resp. compensation)
Example of Metabolic alkalosis?
loss of acid by vomiting
During Respiratory Compensation of Metabolic alkalosis, ventilatory rate will _____ and pCO2 will ________.
Decrease

Decrease
Renal response of Metabolic alkalosis will?
reduce plasma bicarbonate by secreting HCO3- into tubule lumen
Net result to renal response of Metabolic alkalosis?
higher than normal pH, pCO2, & HCO3-
Respiratory disorders with acid/base balance
Respiratory acidosis
Respiratory alkalosis
Respiratory acidosis is caused by
Hypoventilation
What is Hypoventilation?
CO2 elimination rate < rate of CO2 production
which will increased pCO2
What is the Buffer Compensation for Respiratory acidosis:
Chemical buffering by the cells and plasma will change HCO3- by about 1mmol/L
For every 10mmHg change in pCO2
Chemical buffering by cells/plasma for Compensation for Respiratory acidosis:
will change HCO3- by about __ mmol/L for every ___ mmHg change in pCO2
1 mMol/L
10 mmHg
If pCO2 has changed from 40 to 60mmHg, then these buffers by themselves will produce an
increase in HCO3- of?
2mmol/L
slight increase in HCO3-
Renal response to respiratory acidosis?
Decrease in plasma [HCO3-] by secretion
Net result of pCO2, HCO3-, and pH of renal response to respiratory acidosis?
higher than normal pCO2
higher than normal HCO3-
lower than normal pH
Respiratory alkalosis is caused by
Decreased CO2
What is Hyperventilation?
CO2 elimination rate < rate of CO2 production
which will increased pCO2
What is the Buffer Compensation for Respiratory alkalosis:
will change HCO3- by the change in pCO2
Chemical buffering by the cells and plasma for Compensation for Respiratory alkalosis:
will change HCO3- by about _ mmol/L
For every __mmHg change in pCO2
1 mMol/L
10 mmHg
Renal response to respiratory alkalosis?
Decrease plasma [HCO3-] by secretion
Net result of pCO2, HCO3-, and pH of renal response to respiratory alkalosis?
lower than normal pCO2
higher than normal pH (not completely compensated)
lower than normal HCO3-
The combination of pH, pCO2 and plasma[HCO3-] of acid/base balance signifies?
the type of disorder (acidosis vs. alkalosis),
the primary cause (respiratory vs. metabolic),
and whether renal compensation has occurred.
Respiratory
alkalosis

pH ~ (G/S/L) ~ normal
HCO3- ~ (G/S/L) ~ normal
pCO2 ~ (G/S/L) ~ normal
pCO2 ~ < normal
pH ~ > normal
[HCO3-] ~ < normal
Metabolic
alkalosis

pH ~ (G/S/L) ~ normal
HCO3- ~ (G/S/L) ~ normal
pCO2 ~ (G/S/L) ~ normal
pCO2 ~ > normal
pH ~ > normal
[HCO3-] ~ > normal
Respiratory
acidosis

pH ~ (G/S/L) ~ normal
HCO3- ~ (G/S/L) ~ normal
pCO2 ~ (G/S/L) ~ normal
pCO2 ~~ > normal
pH ~ < normal
[HCO3-] ~~ > normal
Metabolic
acidosis

pH ~ (G/S/L) ~ normal
HCO3- ~ (G/S/L) ~ normal
pCO2 ~ (G/S/L) ~ normal
pCO2 ~ < normal
pH ~ < normal
[HCO3-] ~ < normal
Akalosis is either due to?
a decreased pCO2,
or an increased plasma bicarbonate
Acidosis is either due to?
an increased pCO2 or to a
decreased plasma bicarbonate
A 21 year old man has had severe diarrhea for several days, and has been brought to the clinic by his concerned roommate. The physicians at the clinic find the following results from lab tests:

Arterial plasma pH ~ 6.98
Plasma [HCO3-] ~ 3 mmol/L
pCO2 ~ 13 mmHg

pH ~ (G/S/L) ~ normal
HCO3- ~ (G/S/L) ~ normal
pCO2 ~ (G/S/L) ~ normal

Condition:
Problem:
Effect:
pH ~ Less than ~ normal
HCO3- ~ Less than ~ normal
pCO2 ~ Less than ~ normal

Condition: Metabolic Alkalosis
Problem:HCO3- is lower than normal
Effect: pCO2 is lower than normal
Mrs. Jones’ patient chart provides the following information:

Arterial plasma pH ~ 7.50
Plasma [HCO3-] ~ 20 mmol/L
pCO2 ~ 30 mmHg

What is her acid/base status?

Acidosis or alkalosis?

Respiratory or metabolic?
pH ~ G ~ normal
HCO3- ~ L~ normal
pCO2 ~ L ~ normal

Alkalosis cause pH is greater than normal

Respiratory
A young woman’s lab tests who the following:
Arterial plasma pH ~ 7.30
Plasma [HCO3-] ~ 36 mmol/L
pCO2 ~ 60 mmHg

What is her acid/base status?
Acidosis or alkalosis?
Respiratory or metabolic?
pH ~ L ~ normal
HCO3- ~ G~ normal
pCO2 ~ G ~ normal

Acidosis cause pH is less than normal

Respiratory
How to analyze these test result questions?
1. examine the pH – determine if it is acidosis or alkalosis

2. examine the pCO2 – is it the primary cause, or a compensatory change?

3. Examine the magnitude of the difference of the HCO3- relative to normal

A HCO3- change that exceed this is a sign of renal compensation
It is not uncommon for people to have acid-base disorders that are both?
respiratory and metabolic
people who have acid-base disorders that are both respiratory and metabolic tend to have?
Many things not working