Physiology - Renal regulation of H+ Flashcards
what is the normal pH of the ECF?
a.7.35 - 7.45
b.2.35-2.45
c.5.35-5.45
a.7.35 - 7.45
what is the pH of the intracellular fluid
a.7.0
b.7.1
c.7.2
d.7.3
c.7.2
more acidic than ECF due to intracellular acid production
the protein buffer system and the bicarbonate buffer system are examples of which type of buffer
a.chemical
b.physiological
a.chemical
in the bicarbonate buffer system what is the role of carbonic anhydrase
a.converts co2 and h2o to carbonic acid
b.converts carbonic acid to bicarbonate and h+
a.converts co2 and h2o to carbonic acid
the renal and respiratory system are examples of which type of buffer
a.chemical
b.physiological
b.physiological
type of buffer have a better buffering capacity
a.physiological
b.chemical
a.physiological
which system stabilises pH by controlling the output of acids and bases
a.respiratory
b.renal
c.bicarbonate
b.renal
which system stabilises pH by controlling the output of volatile acids including co2
a.respiratory
b.renal
c.bicarbonate
a.respiratory
which physiological buffer has a better buffering capacity
a.renal
b.respiratory
c.bicarbonate
d.protein
a.renal
but takes several hours to days
resp effective within minutes
in normal control of pH there is a small excess of what substance in the body leading it to be filtered at the glomerulus
a.H+
b.H2CO3
HCO3-
a.H+
filtered along with HCO3-
what happens to H+ in the filtrate
recombines with HCO3- to make H2CO3
H2CO3 dissociates into H2O and CO2
both diffuse into the tubular cell
what are H2O and CO2 converted to by carbonic anhydrase inside the tubular cell
a.H+ and HCO3-
b.H2CO3
b.H2CO3
then dissociates into HCO3- and H+
which substance diffuses from the tubule cell into the blood when the renal system is acting as a buffer
a.H+
b.HCO3-
c.H2CO3
d.H2O
b.HCO3-
which substance diffuses into the blood from the tubule cells when the renal system acts as a pH buffer
a.H+
b.HCO3-
c.H2CO3
d.H2O
a.H+
combines with HCO3- and cycle starts again
what is the net effect of when the renal system acts as a physiological buffer
A.H+ secreted, HCO3- reabsorbed
b. H+ excreted, HCO3- reabsorbed
c.HCO3- secreted, H+ reabsorbed
A.H+ secreted, HCO3- reabsorbed
urine is
a.acidic
b.alkali
a.acidic
H+ secretion> reabsorption
During acidosis renal correction
all available HCO3- combines with H+
extra CO2 in filtrate reabsorbed
in the tubule cells extra H2CO3 made so more H+ and HCO3- made
more HCO3- into blood to make it less acidic
H+ secreted into filtrate
no more HCO3- to combine with so excreted in urine and urinary pH lower
ECF pH returned to normal
what happens to urinary pH if acidosis is being corrected via the renal buffering system
a.increase
b.decrease
b.decrease
more CO2 combining with more H2O outside tubule cells
more into tubule cells to be converted to h2co3 and then H+ and HCO3-
more H+ secreted back into filtrate but no more HCO3- to combine with
so excess H+ is excreted in the urine
and ECF H+ returns to normal
for H+ secretion what needs to be maintained
a.H+ conc gradient (lower in filtrate than blood)
a.H+ gradient (lower in blood than filtrate)
a.H+ conc gradient (lower in filtrate than blood)
a pH of below what will stop H+ secretion and therefore limit the resorption of HCO3-
a.4.5
b.5.5
c.6.5
a.4.5
(high amount of H+ in filtrate so no gradient between this and the blood)
when H+ is in excess in the filtrate and the gradient no longer is enogh for secretion H+ is combined with which substance in order to excrete it?
a.HCO3-
b. NH3
c.NH4+
b. NH3
from breakdown of amino acids
secreted by renal tubular cells
combined with H+ to form NH4+
Excreted in the urine
the binding of which ion to plasma proteins is affected by a drop in pH
a.sodium
b.calcium
c.potassium
d.bicarbonate
b.calcium
what happens to free calcium levels when H+ levels increase (uncompensated acidosis)
a.increase
b.decrease
b.calcium
H+ dispalces Ca2+ on albumin
Ca2+ is then free and blocks sodium channels reducing their opening
reduced AP firing in myocytes and nerves
bradycardia and asystole
stupor and coma
what is the effect of the increased in free calcium in uncompensated acidosis binding to nerves and myocytes
a.more excitable
b.less excitable
b.less excitable
blocks sodium channels and reduces their opening
which channels are blocked by free calcium in uncompensated acidosis
a.sodium
b.potassium
c.calcium
a.sodium
what type of acidosis could be caused by ventilatory failure or COPD
a.respiratory
b.metabolic
a.respiratory
renal injury, aspirin overdose, diarrhoea and alcoholism are possible causes of which type of acidosis
a.respiratory
b.metabolic
b.metabolic
renal correction of alkalosis process
decreased H+ in filtrate means less H2CO3 formed in filtrate
less co2 and h2o formed in filtrate
less H2CO3 formed by carbonic anhydrase in the tubular cells
less HCO3- made and so less reabsorbed
less H+ made so less secreted (whil H+ made continuosly by body so increase in plasma H+)
surplus HCO3 excreted
what happens to amount of free calcium in uncompensated alkalosis
a.increase
b.decrease
b.decrease
less H+ bound to plasma proteins so more Ca2+ binds to plasma proteins
less free Ca2+
less blockage of sodium channels so increased opening and increased AP firing
increased nerve and myocyte activity
confusion, muscle spasms , death
what can hyperventilation cause
a.respiratory acidosis
b.respiratory alkalosis
c.metabolic alkalosis
d.metabolic acidosis
b.respiratory alkalosis
what can antacid overdose, hyperaldosteronismand vomiting cause
a.respiratory acidosis
b.respiratory alkalosis
c.metabolic alkalosis
d.metabolic acidosis
c.metabolic alkalosis
patient has arterial blood sample with ph >7.4, PCO2 <40 mmHg , and HCO3- <24
what type of alkilosis is this
a.respiratory
b.metabolic
a.respiratory
patient has arterial blood sample with ph >7.4, PCO2 <40 mmHg , and HCO3- <24
what is the likely cause
a.hyperventilation
b.COPD
c.antacid overdose
d.renal disease
a.hyperventilation
acidosis or alkalosis? - alkilosis
co2 low = alot being blown off at lungs so hyperventilation
HCO3 low
as less HCO3- is being reabsorbed to compensate for the alkilosis going on elsewhere ie resp
patient has arterial blood sample with ph >7.4, PCO2 >40mmHg , and HCO3- >24mmHg
what is the likely cause
a.hyperventilation
b.COPD
c.antacid overdose
d.renal disease
c.antacid overdose
high pH so alkalosis
metabolic or resp?
hco3- - high so metabolic
pco2 high so must be resp compensation for metabolic alkalosis
patient has arterial blood sample with ph <7.4, PCO2 >40mmHg , and HCO3- >24mmHg
what is the likely cause
a.hyperventilation
b.COPD
c.antacid overdose
d.renal disease
ph <7.4 = acidosis
metabolic or resp?
high pco2 - not much blown off in lungs
high hco3- - renal compensation for this
so resp
b.COPD
patient has arterial blood sample with ph <7.4, PCO2 <40mmHg , and HCO3- <24mmHg
what is the likely cause
a.hyperventilation
b.COPD
c.antacid overdose
d.renal disease
acidosis as pH<7.4
metabolic or resp
HCO3- low so not much alkali hco3- reabsorbed and acidosis is metabolic
pco2 - low so alot of CO2 being blown off so a resp compensation and acidosis must be elsewhere
