Renal System 5 renin pt 2(3)

Question 1

How does the kidney maintain the pH balance?

Answer 1

if pH is too low (acid) -> the kidney will add HCO3-
if pH is too high (basic) -> the kidney will ad CO2

Question 2

What concept is used to maintain pH?

Answer 2

Reabsorbtion of HCO3- (bicarbonate)
it actually only looks like reabsorption

Question 3

How does the kidney get (reabsorb) bicarbonate HCO3- into the interstitial fluid?

Answer 3

1) H20 + CO2 -> H2CO3 (carbonic acid) -> H+ and HCO3-
H+ gets secreted to the apical side and forms H2CO3 with HCO3-
HCO3- gets to the basolateral side (considered reabsorbed)

Question 4

How does the kidney form new bicarbonate when the pCO2 level is high? -> brings base HCO3- to increase pH

Answer 4

1) split of H+ and HCO3- by carbonic anhydrase
H+ goes to the apical side and binds to HPO4 -> H2Po4
HCO3- gets to the basolateral side
f.e. in case of a breathing disorder

2) Glutamine goes from the tubular lumen to the epithelial cell -> is split into NH4+ and HCO3-
NH+4 gets back to the apical side and HCO3- to the basolateral side (reabsorbed)

Question 5

What are common ways to change pH?

Answer 5

Diarrhea and loss of HCO3- -> acidosis
Vomiting and loss of H+ -> alkalosis

acidosis: excessive protein breakdown, lactic acid production, Metformin (drug) causes lactic production, Hypoventilation raises CO2

alkalosis: Hyperventilation lowers CO2

Question 6

When does the kidney or the lung compensate pH?

Answer 6

Respiratory imbalance: The kidney compensates by changing HCO3-

Metabolic imbalance: Lungs compensate by changing pCO2

Question 7

Explain the Davenport plot:

Answer 7

The change of pH is described by movement on the Bufferline, the Bufferline describes the level of HCO3-, if pH goes down HCO3- goes up to compensate

Question 8

How does the pH move in case of acidosis or alkalosis on the plot?

In case of respiratory imbalance!

Answer 8

In the case of acidosis: breathing in less O2 -> CO2 goes up
They are stuck on the isopleth, which means they cant compensate by Hyperventaltion, and the pCO2 stays high -> causing a big shift to the top because of a big increase of HCO3- to get back to normal

In the case of alkalosis: Hyperventilation -> loss of CO2
The kidney will compensate by reducing HCO3- - staying on the isopleth (same pCO2)

CHANGE OF HCO3 level!

Question 9

How does the pH move in case of acidosis or alkalosis on the plot?

In case of metabolic imbalance!

Answer 9

In case of metabolic acidosis: HCO3- would be decreased and they would move along the buffer line back to normal

In case of metabolic alkalosis: HCO3- would be increased and to restore the pH they move along the buffer line

CHANGE OF PCO2 level!