Brainscape's Knowledge GenomeTM

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


See full index

Semester 3 - Urinary > Session 6 - Acidosis and Alkalosis > Flashcards

Session 6 - Acidosis and Alkalosis Flashcards

1
Q

How do the kidneys control plasma volume?

A

• Filtering and variably recovering salts

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

How do the kidneys control plasma osmolarity?

A

• Filtering and variably recovering water

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

How do the kidneys variably control plasma pH?

A

• Filtering and variably recovering hydrogen carbonate and active secretion of hydrogen ions

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

What is normal pH range?

A

• 7.38 - 7.42

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

When does alkalaemia occur?

A

> 7.42

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

When does acidaemia occur?

A

• <7.38

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

What is normal conc of H+?

A

37-43 nmol/l

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

Outline what occurs in alkalaemia

A

• Lowers solubility of Ca2+ salts, free Ca2+ binds to proteins. Results in hypocalcaemia
○ Increases excitability of nerves
• Paraesthesia
• Tetany

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

What is % mortality at pH 7.55?

A

45%

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

What is % mortality at pH 7.65?

A

80%

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

Outline what occurs in acidaemia

A

• Hyperkalaemia (heart arrythmias and arrest)
• Affects many enzymes
○ Reduces cardiac and skeletal muscle contractility
○ Reduced glycolysis in many tissues
○ Reduced hepatic function
• Effects severe under 7.1
• Life threatening below pH 7.0

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

How much HCO3- is required for accurate pH maintenance?

A
  • 20x as much HCO3- as there is CO2
    • pH = pK + log (HCO3-/pCO2 x 0.23)
    • Log 20 (20x higher) = 1.3
    • pK - 6.1 + 1.3 = 7.4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is CO2 determined by?

A
  • Controlled by chemoreceptors

* Disturbed by respiratory disease

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

What is HCO3- conc determined by?

A

• Controlled by kidney

Disturbed by metabolic and renal disease

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

What is HCO3- largely created by?

A

• Red blood cells

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

What is respiratory acidaemia (acidosis)?

A
  • Hypoventilation leads to hypercapnia
    • Hypercapnia causes plasma pH to fall
    • Less than 20x amount of HCO3-
    • pH <7.35
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is respiratory alkalaemia (alkalosis)?

A
  • Hyperventilation leads to hypocapnia
    • Fall in pCO2 causes pH to rise
    • More than 20x amount of HCO3- than CO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is normal pH?

A

7.38 - 7.42

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

What is normal HCO3-

A

• 22 - 29 mmol/l

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

What is normal pO2?

A

• 9.8 - 14.2 kPa

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

What is normal pCO2?

A

• 4.2 - 6.0 kPa

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

How is pH corrected in respiratory alkalosis/acidosis?

A
  • Central chemoreceptors normally control pCO2 within tight limits
    • Peripheral chemoreceptors enable changes in respiration driven by changes in plasma pH
    • This is CORRECTION - Changing the factor at hand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is pH compensated in respiratory acidosis/alkalosis

A
  • changes in pCO2 compensated by changes in HCO3-
    • Kidney control HCO3-
    • Respiratory acidosis is compensated by kidneys increasing HCO3-
    • Respiratory alkalosis is compensated by kidneys decreasing HCO3-
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is metabolic acidosis?

A
  • Tissues produce acid (or acid in blood - amino acids)
    • H+ reacts with HCO3-, leading to fall in pH

Metabolic acidosis

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

How is metabolic acidosis compensated (acidosis means alteration in buffer base!)?

A

• Compensated by changes in ventilation
○ Peripheral chemoreceptors increase ventilation
○ This lowers pCO2

Restores pH towards normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is metabolic alkalosis caused by?

A
  • Plasma HCO3- rises (after vomiting for instance)
    • Plasma pH rises
    • Metabolic alkalosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How is metabolic alkalosis compensated?

A

• Partially compensated by decreased ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How are respiratory changes in pH changed? (use correct terminology)

A
  • Compensated by kidney

* Corrected by breathing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How are metabolic changes in pH modified? (use correct terminology)

A
  • Compensated by breathing (changing factor than other directly changes)
    • Corrected by kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is produced in metabolic acidosis?

A
  • H+ ions which react with HCO3- to produce CO2 in venous blood
    • CO2 breathed out, proportionally reducing HCO3-
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Why can metabolic alkalosis only be partially compensated?

A
  • Because can only slightly reduce respiratory to increase CO2
    • At risk of hypoxia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How much HCO3- filtered per day?

A

• 4500 mmol

33
Q

How can HCO3- be increased?

A

• Recover all filtered HCO3-

Make new

34
Q

Give two ways in which kidneys synthesise HCO3-

A

• Amino acids

CO2

35
Q

How do the kidneys make new HCO3- from CO2?

A
  • Kidneys produce a lot of CO2
    • Combined with water to produced H2CO3-
    • H+ excreted into water, HCO3- into blood
36
Q

How do the kidneys make new HCO3- from amino acids?

A
  • Glutamine

* Produces NH4- to enter urine, HCO3- excreted into blood

37
Q

Where is HCO3- recovered in kidney?

A
  • 80-90% in PCT

* Remainder in thick ascending limb of loop of henle

38
Q

How is HCO3- recovered in PCT of kidney?

A

• H+ exported from cell into lumen via Na-H antiporter
○ Up conc grad
○ Energy from movement of Na+ down Conc grad (Na/K+ ATPase on basolateral membrane
• H+ reacts with HCO3- in lumen, making CO2 + H20
• CO2 enters cell, reacts with H20 to make HCO3-
• HCO3- exported with K+ into ECG

39
Q

How is HCO3- created from amino acids in the PCT?

A 
• Glutamine broken down to produced
		○ A-ketoglutarate (HCO3-)
		○ Ammonium (NH4+)
		○ HCO3- into ECF
		○ NH4+ into lumen
40
Q

What does HCO3- reabsorption look like in PCT?

A

• DRAW IT NOW

41
Q

What has happened to HCO3- by the time of the DCT?

A

Has almost all been filtered and recovered

42
Q

How is HCO3- recovered in distal tubule cells?

A
  • CO2 produced and combined with H20 to make H2CO3-
    • Na+ gradient insufficient to drive H+ secretion
    • H+ actively transported out of cell via H+ ATPase and H+/K+ antiporter
    • H+ bound to HPO42- + H+ -> H2PO4- in lumen
43
Q

What happens to K+ when cells export H+?

A

• K+ is absorbed into blood

44
Q

Why may you end up absorbing a large amount of K+?

A

• If a large amount of HCO3- needs to be reabsorbed due to respiratory acidosis, large amount of K+ will be reabsorbed with it. May cause hyperkalaemia

45
Q

What is minimum urine pH

A

4.5

46
Q

What is a titratable acid?

A

• One which can freely gain H+ ions in an acid/base reaction

47
Q

How is H+ buffered in urine?

A
  • HP04 2- -> H2PO4-

* NH3 -> NH4+(ammonia -> ammonium)

48
Q

What is daily acid secretion?

A

• 50-100mmol H+

49
Q

How is H+ excretion controlled?

A
  • pH detected by intracellular pH of tubular cells

* Change in rate of HCO3- export to ECF produced by changes in ECF (H+ automatically excreted)

50
Q

How is respiratory acidosis associated with K+?

A
  • Causes hyperkalaemia
    • HCO3- being generated, H+ being expelled

K+ taken in in exchange for H+

51
Q

How is metabolic alkalosis associated with hypokalaemia?

A

• Hypokalaemia

52
Q

How does hyperkalaemia cause metabolic acidosis?

A
  • As K+ rises, kidneys ability to reabsorb and create HCO3- reduced.
    • Hyper kalaemia makes intracellular pH alkaline, favouring HCO3- excretion
53
Q

How does hypokalaemia cause metabolic alkalosis?

A

• Hypokalaemia makes intracellular pH acidic, favouring H+ excretion and HCO3- recovery

54
Q

Draw activities of DCT

A

NOW

55
Q

Give 4 cellular responses to acidosis

A

• Enhanced H+/Na+ exchange
○ Full recovery of all filtered HCO3-
○ Enhanced ammonium production in PCT
○ Increased activity of H+ ATPase in distal tubule
○ Increased activity of H+ ATP-ase from tubular cells to ECF

56
Q

What is metabolic acidosis due to?

A
  • Fall in HCO3-

* A gain in H+

57
Q

What is metabolic alkalosis due to?

A
  • Due to rise in HCO3-

* A fall in H+

58
Q

Give an outline of metabolic acidosis

A
  • Acids produced metabolically
    • Produced from H+ and an anion (lactate, ketones)
    • H+ reacts with HCO3-, producing CO2 which is breathed out

Some HCO3- replaced by anion from acid

59
Q

What happens to HCO3- after vomiting?

A
  • Large increase in HCO3- and as replacement H+ produced
    • Kidneys cannot excrete HCO3- as they are trying to compensate for dehydration
    • HCO3- and Na+ recovery is favoured to increase osmolarity of plasma and cause osmotic movement of water
    • Metabolic alkalosis ensues
60
Q

How can you treat metabolic alkalosis after vomiting?

A
  • Rehydration

* Post rehydration HCO3- will be excreted quickly

61
Q

Why does HCO3- increase after persistent vomiting?

A
  • H+ decreased in stomach
    • More H+ produced, releases HCO3- into blood
    • Hypokalaemia ensues
62
Q

Why does hypokalaemia occur as a result of vomiting?

A

• H+ secretion in kidney stops, so does K+ reabsorption (Antiporter, intercalated cells)

63
Q

Why do side effects of vomiting include hypokalaemia?>

A
  • H+ secretion in kidney stops, so does K+ reabsorption
    • More K+ lost in urine
    • Hypokalaemia
64
Q

Give three causes of metabolic acidosis

A
  • Excess metabolic production of acids
    • Acids are ingested (amino acids)
    • Problem with the renal excretion of acid
65
Q

What is the anion gap?

A

• Indicates whether an HCO3- has been replaced with something other than Cl-

66
Q

How is the anion gap calculated?

A

• Difference between (Na+ + K+) and (Cl- + HCO3-)

67
Q

What is the normal value of the anion gao?

A

• 10-15 mmol/l

68
Q

When is the anion gap increased?

A

• If anions from metabolic acid has replaced plasma HCO3-

69
Q

hen can renal problems reduce HCO3- without increasing the anion gap?

A

If HCO3- replaced with Cl-

70
Q

Give four causes of an increased anion gap metabolic acidosis

A
  • Lactate
    • Ketoacids
    • Toxic alcohols
    • Aspirin
71
Q

What is renal correction of low pH?

A

• Fall in tubular cell intra-cellular pH stimulates acid secretion and HCO3- recovery, thus raising plasma HCO3-

72
Q

How can metabolic alkalosis occur?

A
  • HCO3- increases after persistent vomiting

* Should be very easy to correct

73
Q

What is the issue with a HCO3- infusion?

A

• Excreted in kidney immediately

74
Q

Why does vomiting compromise ability to excrete HCO3-?

A
  • Vomiting also causes dehydration
    • Volume depletion. Capacity to lose HCO3- is less, because high rates of recovery favour HCO3- recovery and H+ secretion
75
Q

How do you treat metabolic alkalosis?

A

• Rehydrate

76
Q

What is a dangerous effect of metabolic acidosis?

A

• Hyperkalaemia
○ K+ moves out of cells, in order to control intracellular pH

More K+ reabsorbed in distal nephron, as a result of H+ excretio

77
Q

What is a dangerous effect of metabolic alkalosis?

A

• Hypokalaemia
○ K+ moves into cells

Less K+ reabsorption (less H+ excreted in distal nephron

78
Q

How does hypokalaemia cause metabolic alkalosis?

A

• Make intracellular pH of tubule cells acidic
○ Favours H+ excretion and HCO3- recovery
○ Therefore metabolic alkalosis occurs

79
Q

How does hyperkalaemia cause metabolic acidosis?

A

• Makes intracellular pH alkaline
○ Favours HCO3- excretion
○ Therefore metabolic acidosis

Semester 3 - Urinary (33 decks)

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