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Flashcards in acid base balance Deck (28):
1

where is bicarbonate reabsorbed

90% in the pct, the rest in the dct

2

what other buffers are there apart from bicarbonate

urate
phosphate
creatinine
beta hydroxybutyrate
proteins
haemoglobin

3

what is fraction of inspired oxygen

the proportion of air that is breathed in which is oxygen
eg room air is 20% which is 0.2

4

what is a healthy p/f ratio

12/ 0.2 = 60

5

what type of blood is the anion gap calculated from

venous

6

what are the features of a normal anion gap acidosis

loss of bicarb
therefore chlorine is retained by the kidneys in order to maintain neutrality of the serum

7

what is renal tubular acidosis

failure of kidneys to excrete acid causes blood acidosis
will not cause an increased anion gap
hypercholaemic

either failure to reabsorb bicarb or failure to secrete acid

8

what type of acidosis would anion gaps be used for

metabolic only

9

what is normal anion gap

16

10

what two substances will cause an increase anion gap when ingested

methanol
ethylene glycol

11

what gap does renal failure cause

increased gap

12

what does the kidney do to bicarbonate

reabsorbs filtered bicarb
regenerates bicarb consumed by buffering

13

why does diarrhoea cause acidosis

for every bicarb ion released into the gut one H+ is released into the ECF
This process is increased in diarrhoea

14

how can the kidneys correct for metabolic acidosis

only if non renal origin and the kidneys are working

secrete more acid into the urine and make new bicarb

15

what is pf ratio

the arterial oxygen partial pressure / fraction of air that is oxygen

normal arterial oxygen is approx. 12
room air is approx. 20% O2

so PF = 12/0.2= 0.6 or 60%

16

where is bicarbonate reabsorbed

PCT (90%) , DCT and collecting duct(10%)

17

what is titratable acid

any acid except for ammonium

18

what is distal renal tubular acidosis

failure to concentrate H+ in the distal tubule

19

what is proximal renal tubular acidosis

impairs PCT reabsorption of bicarbonate

most common in children

20

what is hyperkalaemic renal tubular acidosis

reduction in aldosterone inhibits NH3 production

most common in adults

21

what factors regulat renal bicarb handling

PCO2, H+, volume of ECF, angiotensin 2, aldosterone, potassium

22

what amino acid is involved in ammonium excretion

glutamine

23

what acid excretion increases greatly during acidosis

ammonium

titratable acid excretion is relatively constant

24

what is glutamine turned into in ammonium secretion

alpha keto glutarate

25

what buffers are found in urine

urate
creatinine
beta hydroxybutarate

26

what part of the kidney is resposible for acid base balance

collecting duct

27

what is the feature of increased anion gap acidoses

the body is producing an acid e.g. lactic acid

28

what could cause maintainance of the alkalosis

potassium/ chloride depletion group which impairs the kidneys ability to secrete bicarb

chloride and bicarb are the only anions present in the ecf therefore must be maintained in order to maintain electrical neutrality