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Flashcards in Acid/ Base Balance Deck (67)
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1
Q

What is the normal pH of arterial blood?

A

7.4

2
Q

What ion does the body produce?

A

H ions

3
Q

Name 2 sources of H in the body?

A

Respiratory acids

Metabolic acids

4
Q

An increase in acidic conditions will do what to ventilation?

A

Increase (breath off CO2)

5
Q

What is a metabolic form of acid?

A

lactic acid

6
Q

On a normal day, what is the net gain of H in the body?

A

50-100mmoles

7
Q

What minimises changes in pH?

A

Buffers

8
Q

What equation defines the pH in terms of ratio A/HA?

A

Henderson-Hasselbalch equation

pH = pK + log (A/HA)

pH §(HCO3)/pco2

9
Q

What is the most important ECF buffer?

A

Bicarbonate

10
Q

What is the ratio of bicarbonate to carbonic acid in the body?

A

20:1

11
Q

What is the standard HCO level in the body?

A

24 mmoles (22-26)

12
Q

What is the normal PCO?

A

40mmHg

13
Q

If there is a reduction in H ions, what will happen to ventilation?

A

Reduce

14
Q

How is H eliminated from the body?

A

From the kidneys

15
Q

What is {HCO} regulated by?

A

Kidneys

16
Q

What is PCO controlled by?

A

Lungs

17
Q

What is exchanged for H moving into the cell? Why?

A

K ions

To maintain electrical neutrality

18
Q

In acidosis, what can occur to the ECF?

A

Increase in K (hyperkalaemia)

19
Q

How do the kidneys regulate HCO?

A

Reabsorb filtered HCO

Generate new HCO

20
Q

What does the reabsorption & generation of new HCO depend on?

A

Active H secretion from tubule into lumen

21
Q

In what form does HCO move across the cell membrane?

A

CO2

22
Q

What is the name of the enzyme responsible for the conversion of CO > H2CO3?

A

Carbonic anhydrase

23
Q

What passes into the peritubular kidneys?

A

Na & HCO3

24
Q

Where does the bulk of HCO reabsorption occur?

A

Proximal tubule

25
Q

How much HCO is filtered per day?

A

4320mmoles

26
Q

How is H ions actively moved across the tubular membrane into the lumen?

A

Na/H antiporter

27
Q

What is the minimum and maximum urine pH?

A
  1. 5

8. 0

28
Q

What weak acids/ bases act as buffers?

A

uric acid
creatinine
dibasic phosphate

29
Q

What is the importance of formation of titratable acidity?

A

Generates new HCO and excretes H

30
Q

In titratable acidity, what molecule is responsible foe excreting H ions?

A

HPO4 (mono basic phosphate)

31
Q

When HCO is reabosorbed, is H lost?

A

No excretion of H

32
Q

Where does the process of titratable acidity occur? When?

A

Distal tubule

Acid overload

33
Q

What is the major adaptive response to acid load?

A

Ammonium excretion

34
Q

What does ammonium excretion generate?

A

Generates new HCO

Excretes H

35
Q

When is ammonium excretion used?

A

Only for acid load

36
Q

What are the properties of NH3+?

A

Lipid soluble

37
Q

What does NH3+ combine with in the lumen?

A

H

Cl

38
Q

What enzyme is responsible for the deamination of glutamine to form NH3?

A

Renal glutamine

39
Q

What is the net outcome of ammonium excretion?

A

H secretion

Generation of new HCO

40
Q

In the proximal tubule, the presence of which symporter allows NH4 to move into the lumen?

A

NH4/NA symporter

41
Q

When ICF pH falls, what happens to renal glutamine activity?

A

Increases

42
Q

How long does it take the kidneys to adapt to changes in pH?

A

4-5 days

43
Q

A decrease in body pH is called??

A

Acidosis

44
Q

An increase in body pH is called?

A

Alkalosis

45
Q

Respiratory disorders affect what?

A

PCO2

46
Q

Renal disorders affect what?

A

HCO

47
Q

A reduction in ventilation would lead to CO2 retention and….

A

Respiratory Acidosis

48
Q

Name a cause of acute respiratory acidosis

A

Drugs - opiates & barbituates

49
Q

Name a change of chronic respiratory acidosis

A

Chronic bronchitis/ emphysema, asthma

50
Q

When an increase in ventilation is observed and CO2 is blown off…… occurs.

A

Respiratory alkalosis

51
Q

An acute cause of respiratory alkalosis is…

A

Voluntary hyperventilation

First ascent to altitude

52
Q

A chronic cause of respiratory alkalosis is …..

A

Long term residence at altitude (inc ventilation due to < PO)

53
Q

What are some of the causes of metabolic acidosis?

A

Diabetic ketoacidosis

Loss of HCO in diarrhoea

54
Q

What is the name of a state of hyperventilation observed during diabetic ketoacidosis?

A

Kussmaul breathing

55
Q

What are some of the causes of metabolic alkalosis?

A
Vomiting 
Aldosterone excess ( H loss)
56
Q

A decrease in pH can be caused by either:

A

A decrease in HCO

Increase in PCO

57
Q

An increase in pH can be caused by:

A

An increase in HCO

Decrease PCO

58
Q

In acidosis, what happens to K levels?

A

Hyperkalaemia

59
Q

What does insulin do to K ?

A

Stimulates cellular uptake

60
Q

In hypovolaemia, aldosterone is secreted and acts on which tansporters at the lumen?

A

Na transporter (in)
H (out)
K (out)

61
Q

What does excess ingestion of liquorice precipitate?

A

Metabolic alkalosis

62
Q

What are cations?

A

Na & K

63
Q

What are anions?

A

Cl & HCO

64
Q

The following blood gas values were seen in a patient. Which simple Acid/Base Disturbance has he got?

pH = 7.32, [HCO-3]= 15 mM, PCO2 = 30mmHg (4kPa)

A

Metabolic acidosis

65
Q

The following blood gas values were seen in a patient. Which simple Acid/Base Disturbance has he got?

pH = 7.32, [HCO-3]= 33 mM, PCO2 = 60mmHg (8kPa)

A

Chronic respiratory Acidosis

66
Q

The following blood gas values were seen in a patient. Which simple Acid/Base Disturbance has he got?

pH = 7.45, [HCO-3] = 42 mM, PCO2 = 50mmHg (6.7kPa)

A

Metabolic Alkalosis

67
Q

The following blood gas values were seen in a patient. Which simple Acid/Base Disturbance has he got?

pH = 7.45, [HCO-3]= 21 mM, PCO2 = 30mmHg (4kPa)

A

Respiratory Alkalosis (acute)