Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

5. ADV PHYS > Acid-base balance > Flashcards

Acid-base balance Flashcards

1
Q

define pH:

A

-ve log of H+ conc (mol/L)

pH = -log [H+]

[H+] = 10 ^ -pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

normal ECF values:

A

~7.4
cell values at 7.2
(60 nM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

arterial blood pH:

A

7.4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

venous blood pH:

A

7.36

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

normal arterial pH maintained btw:

A

7.35 - 7.45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

acidotic and fatal pH:

A

<7.35 acidotic

<6.8 is fatal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

alkalotic and fatal pH:

A

> 7.45 alkalotic

>8 is fatal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

reactions increasing net body acid: list (5)

A
  • aerobic metabolism of carbs, fats, neutral aa to
  • sulphur w aa
  • aa w cationic side groups
  • phospholipids, phosphorylated proteins
  • incomplete metabolism of carbs during anaerobic exercise
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

reactions increasing net body acid: aerobic metabolism of carbs, fats, neutral aa to produce-

A

CO2 in CAC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

reactions increasing net body acid: sulphur w aa produce-

A

produced H2SO4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

reactions increasing net body acid: aa w cationic side groups produce-

A

produce urea and H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

reactions increasing net body acid: phospholipids, phosphorylated proteins produce-

A

H2PO4-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

reactions increasing net body acid: incomplete metabolism of carbs during anaerobic exercise produce-

A

produce lactate and H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

major fuel source in diabetics:

A
  • fats for ATP prod
  • acetoacetic acid, ß-hydroxybutyric acid (ketoacids aka ketone bodies) also produced
  • true in starvation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

reactions increase net body base: list (2)

A
  • breakdown aa w anionic side groups

- metabolism of organic anions (eg. citrate, ascorbate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

reactions increase net body base: breakdown aa w anionic side groups produce-

A
  • consumes H+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

reactions increase net body base: metabolism of organic anions (eg. citrate, ascorbate) produce-

A
  • produces HCO3-
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

base/acid excess: diet rich in meat/protein vs. vegetarian

A

protein: excess acid (non-carbonate, non-volatile)
veggie: slight base excess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

loss of: vomiting

A

loss of HCl (acid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

loss of: diarrhoea

A

loss of NaHCO3 (base)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

pH homeostasis: maintained by list (3) and time taken

A
  • immediate neutralisation of added base/acid by buffers (secs)
  • continuous controlled removal of CO2 by lungs (mins)
  • maintenance of ECF [HCO3-] by kidneys (hrs to days)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

pH homeostasis: long term features

A
  • homeostatic control of ECF pH requires balancing endogenous (from aerobic respiration)
  • exogenous (food) input of acid and base w their output from body
  • instantaneous pH regulation vital
  • physiological processes take time
  • chemical buffering is interim measure to ensure pH remains in narrow range
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

buffering: acids defined as

A

H+ donors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

buffering: bases defined as

A

H+ acceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

conjugate acid base equation:

A

acid base + H+

26
Q

buffering: what acts as pH buffers

A

conjugate acid/base pairs of weak acids

27
Q

acid dissociation constant (equilibrium constant) equation

A

Ka= [base] x [H+] ÷ [acid]

28
Q

ECF buffers: list (3)

A
  • HCO3-/ CO2
  • proteins esp haemoglobin, albumin
  • H2PO4-/ HPO42-
29
Q

which buffer accounts for 90% of ECF’s buffering capacity btw pH 7.2-7.6

A

HCO3-/ CO2

30
Q

ECF buffers: haemoglobin sig

A
  • next most important after HCO3-/ CO2
  • histidine residues act as buffers in haemoglobin
  • 36 in each haemoglobin
  • buffers btw pKa values of 6.5
  • haemoglobin buffers acid derived from CO2
  • therefore CO2 produced by cellular metab buffered by haemoglobin while being transported by blood to lungs for excretion
31
Q

bicarbonate buffering sys: what is buffered in this sys

A

H+ from non-carbonate acids

32
Q

bicarbonate buffering sys: equation

A

H2O + CO2 H2CO3 HCO3- + H+

33
Q

bicarbonate buffering sys: HCO3-/ CO2 sys highly effective coz (2)

A
  • conc of HCO3- in plasma is high (24mM)

- operates as regulated open sys, kidney controlling [HCO3-] and respiratory sys controlling plasmaCO2

34
Q

controlled removal of CO2:

A
  • by respiratory sys

- within body pCO2 controlled by resp sys in response to arterial (eventually CSF) pH

35
Q

pH stabilisation in body: continued input of acid

A
  • HCO3- continually consumes to buffer non-carbonic acids
36
Q

pH stabilisation in body: role of kidney list (3)

A
  • HCO3- filtered into kidney tubules reabsorbed, not lost to body
  • additional HCO3- molecules created by kidney tubule cells, transported into plasma to replenish alkaline store
  • non-carbonate acids r excreted
37
Q

pH stabilisation in body: to increase body HCO3- lvls

A
  • organic anions (bases) added to body r metabolised to HCO3-
38
Q

pH stabilisation in body: excess HCO3- removed by

A
  • allowing appropriate amount of HCO3- filtered into kidney tubule to be excreted
39
Q

reabsorption of filtered HCO3-: conc of HCO3- higher in plasma or ECF?

A

plasma

- 24mM

40
Q

reabsorption of filtered HCO3-: how much filtered HCO3- reabsorbed?

A

almost completely

41
Q

reabsorption of filtered HCO3-: depends on? and locations

A
  • from tubular fluid active transport of H+ into tubular fluid
  • LUMINAL Na/H antiport in proximal tubule and luminal H+ pump in collecting duct
42
Q

reabsorption of filtered HCO3-: most of reabsorption occurs in

A

proximal tubule

43
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: how is H+ transported into lumen

A
  • actively transported

- bound by basic form of non-carbonate buffers (mainly HPO4 2-)

44
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: HCO3- generated in cell?

A
  • to produce H+ for export = net increase in HCO3-

- ‘new’ HCO3- ion transported into blood

45
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: HCO3- reabsorption, location

A
  • tranporter on LUMINAL membrane
  • Na/H antiport in proximal tubule
  • also proton pump in collecting duct
46
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: luminal Na/H antiport only secrete at?

A
  • against modest pH grad so tubular fluid (proximal tubule) not fall below 6.8
47
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: H+ pump can produce tubular fluid pH low as, where?

A

4.5 in collecting duct

48
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: titratable acids have pKa values btw, sig?

A
  • 4.5-7.4 (pH of glomerular filtrate)

- effective buffers at pH of urine

49
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: list titratable acids (4) and key

A
  • urate
  • creatine
  • beta-hydroxybutarate
  • HPO4 2-

will bind to H+ in tubular fluid

50
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: pKa- urate

A

5.8

51
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: pKa- creatine

A

5

52
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: pKa- betahydroxybutarate

A

4.8

53
Q

excretion of titratable (non-carbonic) acid/ HCO3- regeneration: pKa- HPO4 2-

A

6.8

54
Q

excretion of ammonium (NH4+)/ HCO3- regeneration: glutamine features

A
  • made from liver, mm and gut
  • taken up from blood into proximal tubule
  • neutral aa w 2 nitrogenous side groups
55
Q

excretion of ammonium (NH4+)/ HCO3- regeneration: glutamine converted into

A
  • å ketoglutarate (AKG2-) w 2x NH4+ produced -> glucose (will consume a H+ in this step)
56
Q

excretion of ammonium (NH4+)/ HCO3- regeneration: glutamine products excreted

A
  • NH4+ ions excreted in urine

- 2x HCO3- (which provided H+ ends up in blood)

57
Q

excretion of ammonium (NH4+)/ HCO3- regeneration: sig of excreting NH4+

A
  • or will be converted into urea in liver= releasing 2x H+ cancelling out HCO3- gained by ECF
58
Q

excretion of ammonium (NH4+)/ HCO3- regeneration: NH4+ is it titratable? and pKa

A
  • NH4+ not titratable acid, v weak acid

- pKa= 9

59
Q

regulation of kidney function: how

A
  • active secretion of H+ into tubular fluid
  • drives HCO3- reabsorption and regeneration is increased by sys acidosis
  • glutamine uptake by tubular cells increased at acidic pH
60
Q

control of cell pH: how does cells maintain pH ~7.2 despite acid producing metabolic processes? list (3)

A
  • rapid efflux of CO2, end product of ox phos
  • intracellular buffering mainly by HCO3-, cellular proteins, organic phosphates (eg. ATP), lesser extent: inorganic phosphates (H2PO4-/ HPO4 2-)
  • exporting H+ via H/Na exchanger
61
Q

summary: (3)

A
  • resp sys reg so daily CO2 prod excreted in expired air (lungs), constant pCO2 is maintained
  • H+ liberated from non-carbonic acids instantly buffered, eventually by HCO3-
  • HCO3- used up replaced in kidney
  • kidney also excretes some acids such as H2PO4-
  • resp and renal sys both maintain body pH by holding ratio of [HCO3-]/[CO2] constant rate

5. ADV PHYS (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions