acid base 1

Question 1

What do the kidneys normally excrete and how much?

Answer 1

acid. 1 mEq/kilo

Question 2

where is bicarb reabsorbed?

Answer 2

80% PT, 15% TAL, 5% CCD, none in urine

Question 3

what are the apical H/bicarb transporters in PT

Answer 3

H/Na antiporter, H atpase (combines w/ bicarb)

Question 4

what are the basolateral H/bicarb transporters in PT?

Answer 4

HCO3/Cl antiporter, HCO3/Na symporter

Question 5

how does H/HCO3 happen in the CT.

Answer 5

alpha and beta intercalated cells. alpha- H/ATPase in apical so secretes acid. Beta- H/ATPase in basal so secretes bicarb via hco3/Cl antiporter

Question 6

what is the most important transporter in CT?

Answer 6

H atpase

Question 7

how does ECF volume contraction affect H secretion and where? Aldosterone? hypokalemia? PTH?

Answer 7

increases it in PT. increases in CT. increase in PT.

Question 8

how does ECF expansion change bicarb reabsorption

Answer 8

inhibits

Question 9

how does aldosterone affect the distal nephron

Answer 9

stimulates H ATPase in intercalated cells and Na reabsorption (na/H antiporter) (secretion).

Question 10

what are the two main urine buffers?

Answer 10

ammonia and titratable acid (Hpo4)

Question 11

how is ammonia formed?

Answer 11

1) NH4+ forms from glutamine in PT and enters tubular fluid 2)NH4+ reabsorbed in LOH 3) NH3 enters CT and gets trapped as NH4+

Question 12

in non-gap acidosis, how much should Cl change? If it isn’t?

Answer 12

increase 1:1 w/ decrease in bicarb. absence of 1:1 relationship means mixed disorder

Question 13

Equation for urine AG? interpretation?

Answer 13

(Na+K)-Cl. Use in Acidosis setting. If UAG is very (-) there is NH4 secretion. If it is (+) or close to 0 then it indicates RTA

Question 14

How is met alk compensated for by kidneys?

Answer 14

^ bicarb absorption from beta intercalated cells.

Question 15

Tx for met alk w/ hypovolemia

Answer 15

Administer NaCl

Question 16

DDx of met alk w/ hypokalemia

Answer 16

diuretics, vomiting (has low urine Cl), bartters

Question 17

what is the henderson hasselbach eq

Answer 17

pH=6.1+log ([HCO3-]/(.03*pCO2))

Question 18

Compensatory response: Met acid, met alk,

Answer 18

Decrease in pCO2=1.2(delta bicarb), Increase in pCO2=0.6(delta bicarb)

Question 19

Compensatory response: Resp acid, resp alk

Answer 19

Acute: Increase in bicarb=.1(delta pCO2), chronic: .4(delta pCO2). Acute: decrease in bicarb=.2(delta pCO2), chronic=.5(delta pCO2)

Question 20

causes of elevated AG acidosis

Answer 20

Methanol, uremia, DKA, Prop glycol, ischemia, Lactic acidosis, Ethanol, salicylates

Question 21

causes of non elevated AG acidosis

Answer 21

Diarrhea, Ureteral diversion, RTA, Hypocapnia, Acetazolamide, Mineralcorticoid deficiency

Question 22

Define Saline responsive met alk and causes

Answer 22

Urine Cl<15. Vomiting, NG suction. diuretics

Question 23

define saline resistant met alk and causes

Answer 23

Urine Cl>20. Hyperaldosteronism, bartter and gitelmans, licorice

Question 24

what does aspirin cause

Answer 24

AG acidosis w/ resp alkalosis