More Acid/Base Reg (lec 17)

Question 1

Respiration is regulated by?

Answer 1

plasma PCO2

Question 2

Respiration PCO2 reg mechanism?

Answer 2

CO2 (acidic) crosses BBB ->
stim medulla chemoreceptors ->
↑ respiration -> ↑ pH

Question 3

What level of HCO3- is “stable”?

Answer 3

22 - 26

Question 4

Renal control of HCO3-: synth of new HCO3-?

Answer 4

response of kidneys to depleted plasma HCO3-

Question 5

Renal control of HCO3-: excretion of HCO3-?

Answer 5

dumps into urine when >26

Question 6

Renal reab of filtered HCO3- mechanism?????

Slide 10

Answer 6

Driven by ICF H+

luminal memb pulls ??????

Question 7

PCT reab of HCO3- mechanism?

Answer 7

HCO3- in cell pumped into blood via:

Na+/HCO3- cotrans and HCO3-/Cl- exchange

Question 8

Slide 13???

Answer 8

???

Question 9

CD reab of HCO3- mechanism?

Answer 9

????

Question 10

⍺-intercalated cells in DCT and CD secrete what?

Reab what?

Answer 10

H+

HCO3-, K+

Question 11

⍺-intercalated cells in DCT and CD secrete H+ how?

Answer 11

Active transport:

Luminal H+ATPase and
Luminal H+/K+ATPase

Question 12

Luminal H+/K+ATPase in DCT and CD moves H+ and K+ where?

Answer 12

H+ into tubule

K+ from lumen into cell

Question 13

Ultimate goal of H+ secretion in DCT/CD?

Once goal pH is reached, what happens to H+ secretion?

Answer 13

drop pH of urine to 4.5

H+ secretion is suppressed

Question 14

Plasma acidosis affects H+ secretion in DCT/CD how?

Answer 14

promotes H+ secretion and synthesis of NH4+

Question 15

Kidneys repair plasma acidosis (low HCO3-) how?

Answer 15

Make new HCO3- and sending it into blood

Excretes H+ as HPO4 (titratable acid) or NH4+

Question 16

Secretion of H+ as titratable acid???

Answer 16

slide 20-21

Question 17

Secretion of H+ as NH4+ (diffusion trapping)?

Answer 17

glutamine metabolized to make 2 NH3 and 2 HCO3-

NH3 -> PCT/CD -> NH4+

NH4+ -> lumen via Na+/H+ exchg -> urine

HCO3- -> baso memb via Na+/HCO3- cotrans -> plasma

Question 18

Synthesis of NH4+ regulated by?

Primary mechanism for dealing w/ what?

Answer 18

intracellular pH:
acidosis stim synth

chronic acid loads (DM ketoacidosis)

Question 19

Relevant anions in determining anion gap?

Relevant cations?

Answer 19

Cl-, HCO3-

Na+

Question 20

Anion response to acidosis from drop in HCO3-?

Answer 20

Cl- increases

Question 21

Acidosis from excess fixed acids results in?

Answer 21

increase in anion gap ->
Cl- levels do NOT change to compensate ->
[HCO3-] drops