Brainscape's Knowledge GenomeTM

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


See full index

PSL301 > PSL301: Water 7 > Flashcards

PSL301: Water 7 Flashcards

Acid-base balance

1
Q

Acid can ___ H+

A

donate

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

Base can ___ H+

A

accept

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

conversion between pH and [H]

A

pH = -log[H]

[H] = 10^(-pH)

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

normal pH in blood

A
  1. 4

7. 35 - 7.45 range

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

most acidic part of body

A

stomach (1.5 pH)

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

most basic part of body fluid

A 
bile (pH = 8)
alkaline urine (pH = 8)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

effect of diet on pH

A

protein - acidic

- sulfur-containing AA are metabolized to H2SO4

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

sulfur containing AA

A
  • cysteine

- methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

1 Met or 1 Cys generates ___ H2SO4

A

1 mol

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

what prevents severe acidosis when we eat proteins?

A

buffers

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

BUFFERS

A

limit the change in [H] when an acid is added/removed from a solution

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

Buffers found in humans

A
  • bicarb (HCO3-)
  • phosphate (HPO4^2-)
  • ammonia (NH3)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

the bicarbonate buffer system is catalyzed by…

A

carbonic anhydrase (CA)

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

Why is the bicarb system so good?

A

both sides of the equilibrium can be independently regulated; no other buffer system has this quality
- this allows for compensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Kidney has 2 effects on bicarb

A
  1. make new bicarb

2. reabsorb filtered bicarb

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

New bicarb is generated by excretion of…

A

H+, buffered by ammonia or phosphate

  • NH4+
  • H2PO4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does kidney make new bicarb?

A
  1. CO2 + H2O -> H+ and bicarb
  2. H+ is secreted into lumen, buffered by ammonia/phosphate
  3. bicarb is exchanged with Na+, reabsorbed into bloodstream
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where does the phosphate we use to buffer come from?

A
  • filtered from plasma

- diet

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

Mechanism of ammonia buffer system, from start to finish

A
  1. NH3 synthesized by proximal tubular cells
  2. Binds with H+, secreted into lumen as NH4+
  3. Reabsorbed in thick ascending limb
  4. NH3 diffuses through medulla
  5. Bind with H+ from MCD
  6. NH4+ trapped in CD lumen, excreted in urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the more important urinary buffer? Why?

A

Ammonia;

  • Phosphate amount is limited and cannot be adjusted
  • Kidneys can regulate amount of ammonia 5-10x
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

ammonium is a weak ___

A

acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

___ freely diffuses across cell membranes & blood vessels

A

ammonia

23
Q

___ does not readily cross cell membranes

A

ammonium

24
Q

in a more acidic environment, there is more ammonia // ammonium

A

ammonium

25
Q

How does ammonia buffer H+?

A
  1. Freely cross into lumen
  2. Bind H+ inside lumen
  3. NH4+ cannot cross back into tubular cell
  4. must be excreted
26
Q

ammonia is synthesized by the…

A

proximal tubular cells from Glutamine

27
Q

For every 1 H+ / 1 NH4+ secreted, ___ bicarb is synthesized

A

1

28
Q

How is H+ secreted by the CD?

A

H+-ATPase

29
Q

Which AA makes ammonia?

A

glutamine

30
Q

What regulates ammonium excretion?

A

acid/base status

- acidosis = ammonia synthesis & H+ secretion in CD (activate H+-ATPase)

31
Q

Cell pH is recognized by ____, which then alters cell function to _____

A

cell receptors;

normalize pH

32
Q

When is ammonium excretion increased?

A
  • metabolic & respiratory acidosis

- higher protein intake

33
Q

when there is a large acid load, ammonium excretion can increase ____ fold, but it takes ___ days to reach maximum

A

5-10;

3-5

34
Q

reabsorption of bicarb happens at…

A

proximal tubule

35
Q

the best place to reabsorb large amounts of solute is at…

A

proximal tubule

36
Q

main proximal tubule Na transporter

A

Na-H exchanger (NHE3)

37
Q

for every 1 H+ secreted, ___ bicarb is reabsorbed

A

1

38
Q

What is the drive for excreting H+ at the proximal tubule?

A

Na-K ATPase keeps intracellular Na+ low, so NHE3 pumps Na+ into cell in exchange for H+ into lumen

39
Q

Difference in mechanism between bicarb reabsorption & regeneration?

A

regeneration: CO2 is from capillary
reabsorption: CO2 is from lumen

40
Q

most common acid-base disorder is…

A

metabolic acidosis

41
Q

3 ways which metabolic acidosis can occur

A
  1. addition of an acid not normally present
  2. kidney can’t secrete ammonium
  3. loss of bicarb through diarrhea
42
Q

Which acids cause metabolic acidosis?

A
  • lactic acid
  • diabetic ketoacidosis
  • methanol poisoning (formic acid)
  • ethylene glycol poisoning (antifreeze)
  • salicylate poisoning (aspirin)
43
Q

excess lactic acid may be the result of…

A

anaerobic glycolysis

  • exercise
  • shock (tissue not oxygenated)
  • liver failure (removes lactate)
44
Q

formic acid can’t be metabolized to…

A

CO2 and H2O

45
Q

ethylene glycol is very dangerous because…

A

it forms poisonous metabolites

46
Q

Why does lactic acidosis happen when there is not enough oxygen?

A
  • build up of pyruvate
  • increased glycolysis to supply ATP
  • increase in NADH that want to be used up (minor effect)
47
Q

Why might cardiac shock result in anaerobic respiration?

A

not enough O pumped by heart

48
Q

causes of lactic acidosis

A
  • low CO (shock)
  • hypoxemia
  • severe anemia
  • exercise
  • drugs that interfere w/ mitochondrial action
  • liver failure
49
Q

site of lactate metabolism

A

liver

50
Q

what happens if there is no respiratory compensation for metabolic acidosis / alkalosis?

A

then there is also respiratory acidosis / alkalosis

51
Q

If toxic alcohols are present in blood stream, how do we cure it?

A

hemodialysis (has to be early enough)

52
Q

main role of kidney in acid-base balance

A

maintain normal blood bicarbonate

53
Q

kidney excretes ___ in order to make new bicarb lost to buffering

A

ammonium

54
Q

the body responds to acid load by…

A
  • buffer with bicarb (rapid)
  • hyperventilating to lower pCO2 (rapid)
  • excrete more ammonium (slow)

PSL301 (29 decks)

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