Physiology - Renal regulation of H+ Flashcards by Jenna Dymond

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

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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

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the protein buffer system and the bicarbonate buffer system are examples of which type of buffer

a.chemical
b.physiological

a.chemical

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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

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the renal and respiratory system are examples of which type of buffer
a.chemical
b.physiological

b.physiological

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type of buffer have a better buffering capacity

a.physiological
b.chemical

a.physiological

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which system stabilises pH by controlling the output of acids and bases

a.respiratory
b.renal
c.bicarbonate

b.renal

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which system stabilises pH by controlling the output of volatile acids including co2

a.respiratory
b.renal
c.bicarbonate

a.respiratory

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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

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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-

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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

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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+

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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-

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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

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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

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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