Acid Base Chem
Ruth Olson
In a person with severe renal artery stenosis, all
would be inc. above normal except:
1.
2.
3.
4.
5.
Plasma [rennin]
Plasma [antiotensin II]
BP in glomerular capillaries
R to blood flow in efferent artertiole
Systemic arterial BP
**When there is autoregulation: when there is a
higher pressure, the arterial won’t constrict
Autoregulation of an Give an ACE inhibitor to the
previous patient might lead to acute renal failure
(reduced kidney function) by:
1.
2.
3.
These are 3 basic way we manage H+ ions. Lungs is a rapid way to
get rid of H+ions. The kidneys is slow and powerful … that’s what
she said.
H+ ions concentration is measured on a logarithmic scale. This
conversion gives you manageable numbers
4.
5.
Inhibiting renal tubule K+ reabsorption
Inc renal resistance to BF
3. Causing plasma proteins to be
excreted in the urine
Causing systemic arterial hypertension
Reducing glomerular filtration rate
Hypertensive patients who receive transplanted
kidneys from normotensive patient donors often
remain normotensive after surgery. Which of the
following is the most likely explanation of the
normalization of blood pressure in these
transplant paitents
1.
2.
3.
4.
5.
6.
Hypoaldosteronism due to
immunosuppression
Loss of sympathetic nerve supply to
kidneys
Central role of kidney sin long-term BP
control
Immune reaction to kidney transplant
Normal stress response after surgery
The power of beet juice.
Concerning the measurement o frenal plasma
flow and GFR:



Think of the buffers of H+ sponges.
In general the buffers prevent non-volatile acids (which
you can’t breathe off) from increasing the [H+] by
47,500 times!
Effectiveness of a buffer system depends on
[reactants] and pK of system and pH of body fluids.
1.
2.
3.
4.
5.
Inulin is a good GFR marker bc it is
feely filtered in the glomeruli and it is
not reabsorbed, or secreted, by the
renal tubules
Inulin concentration in the proximal
tubules lumen inc. progressively as
water is reabsorbed in that segment of
the nephron
PAH is a good marker of renal plasma
flo because it is freely filtered and is
rapidly secrete by the proximal tubule;
as a result very little PAH reaches the
renal vein
A and C are correct
All are correct
Acid Base Chem
Ruth Olson
Bicarb:


Is the most important buffer in extracellular fluid
even though the concentration of the components
are low and pK of the system is 6.1, which is not very
close to normal extracellular fluid pH (7.4).
Reason: the components of the system (CO2 and
HCO3-) are closely regulated by the lungs and kidneys
There are bicarb transporters. There is a H+/Na+ antiporter as
well.
Remember that for one bicarb to be absorbed you have to have
one H. No new bicarb.
Doesn’t give you the ability to eliminate non-volatile acids
kidneys do!
Transport of the H in the more distal parts of the nephron uses a
primary active transporter. Intercalated cells H+ ion secretion.
It’s important to recognize that pH is generally normal in the
tubular fluid.
Regulation of H+
Bulk of bicarb reasborp is in proximal tubule 85%

Inc pCO2 inc. H+ secretion respiratory
acidosis (you compensate via renal HCO3reabsorption or formation; can’t fix it via
hyperventilating)
Acid Base Chem
Ruth Olson


Inc EC H+ increases H+ secretion
metabolic (can compensate by
hyperventilation) or respiratory acidosis
Inc tubular fluid buffers inc H+ secretion 
metabolic or respiratory acidosis.
Renal Compensations for Acid-Base Disorders



Acidosis:Inc. H+ secretion & Inc HCO3reabsorption and production
o All HCO3- is titrated and excess H+
in tubule is buffered
o Cl- is also secreted
o Buffers other than bicarb generate
new bicarb
Alkadosis: Dec H+ secretion & Dec. HCO3reabsorption and HCO3- loss in urine
Importance of Renal Tubular Buffers:
without them, to excrete > 60mmol nonvalatile acids each day as free H+, we’d
need to excrete 2000 L/ day!
One new bicarb and elimination of one H+
Buffers other than bicarb generate a new bicarb!

Buffering of secreted H+: filtered PO4and generation of “new” HCO3-
Enzymes that break down glutamine are
activated by acidosis
Acid Base Chem
Ruth Olson
One new bicarb for each H excreted. Total of
three.
Every H secreted creates a bicarb.