acid base balance Flashcards

1
Q

what is an acid?

A

proton donator

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

what is a base?

A

proton acceptor

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

what is pH?

A

-log10[H+]

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

what does a lower pH mean?

A

acidic

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

what does a higher pH mean?

A

alkali

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

what is the ECF pH range?

A

7.35-7.45

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

what is acidosis?

A

when pH falls below 7.35

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

what is alkalosis?

A

when pH rises above 7.45

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

what are metabolic sources of H+?

A

carbohydrates - carbonic and lactic acid
proteins - sulfuric acid
fats - acidic ketone bodies
DNA - sulfuric acid

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

what are the systems in place to regulate H+ levels?

A

chemical buffers

acid excretion: renal or respiration

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

what is a buffer?

A

a solution that is resistant to small changes in pH

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

what does an acidic buffer contain?

A

weak acid and conjugate base

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

what does a basic buffer contain?

A

weak base and its conjugate acid

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

what buffers are in the body?

A

phospate
protein
bicarbonate
haemoglobin

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

what is the phosphate buffer equation?

A

H+ + HPO4^2- –> H2PO4^2-

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

explain how protein buffers work?

A

if pH falls (too acidic) - amine group of protein acts as a base and accepts a proton (NH3+)

if pH rises (to alkali) - carboxyl group acts as an acid and donates a H+

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

why does the protein buffer system have such a large effect?

A

bc there are so many proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what sources can bicarbonate buffer system buffer H+ from?

A

any source other than CO2

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

put the buffers of the body in order of highest to lowest buffer capacity

A

bicarbonate - majority
haemoglobin
protein
phosphate - least bc its in the kidneys

20
Q

what is the equation for the haemoglobin buffer system?

A

Hb + H+ –> HHb

21
Q

what is HHb?

A

deoxyhaemoglobin

22
Q

why is the haemogloin buffer system helpful?

A

bc Hb is actively pumped around the body

23
Q

what is the normal range of CO2 in the blood?

A

35-45mmHg = 4.7-6.0kPa

24
Q

how do the lungs help in acid-base balance?

A

eliminating or retaining CO2 by changing the rate or depth of respirations

25
Q

why are the lungs quick at changing acid base balance? what limits this?

A

quick bc the brain can change respiratory rate quickly

limited by the amount of CO2 expired at one time

26
Q

how do the kidneys maintain acid-base balance?

A

by excreting or conserving bicarbonate and hydrogen ions

27
Q

what is the henderson hasselbach equation?

A

acidity is inversely proportional to bicarbonate/carbon dioxide

28
Q

what do you diagnose an acid base disorder?

A

clinical history
targeted physical exam
ABG

29
Q

what is the mechanism of respiratory acidosis?

A

hypoventilation - more CO2 retained

or more CO2 produced

30
Q

what are the causes of respiratory acidosis?

A
COPD
neuromuscular disorder
respiratory centre depression
Late acute respiratory distress syndrome
inadequate mechanical ventilation
sepsis/burns
31
Q

how will respiratory acidosis present?

A
  • CO2 retained, pCO2 is high

- low pH

32
Q

what is the compensatory mechanism of respiratory acidosis?

A

renal
less HCO3- produced (more resorbed)
some respiratory compensation –> increased ventilation rate

33
Q

what is the mechanism of respiratory alkalosis?

A

hyperventilation

34
Q

what are the causes of respiratory alkalosis?

A
anxiety, stress or pain
elevated body temp
overventilation with ventilator
CNS trauma or tumour
Hypoxemia
35
Q

how will respiratory alkalosis present?

A

pH rises

pCO2 falls

36
Q

what is the compensation mechanism of respiratory alkalosis?

A

renal

HCO3- secreted (less reabsorbed)

37
Q

what is the mechanism of metabolic acidosis?

A

Increased H+ –> more acid production or retention

Bicarbonate loss

38
Q

what are the causes of metabolic acidosis?

A

conditions that increase blood acids - renal failure, diabetic ketoacidosis, starvation and lactic acidosis

chronic diarrhoea
toxins
carbonic anhydrase inhibitors

39
Q

how will metabolic acidosis present?

A

low pH
bicarbonate falls
decreased CO2

40
Q

how is metabolic acidosis corrected?

A

hyperventilation

CO2 decreased

41
Q

what is the mechanism of metabolic alkalosis?

A

HCO3- is elevated bc carbohydrate retention or loss of acid

42
Q

what causes metabolic alkalosis?

A
  • acid loss due to vomiting or gastric suction
  • loss of potassium due to steroids or diuresis
  • overuse of antacids
43
Q

how does metabolic alkalosis present?

A

high pH

high HCO3-

44
Q

how is metabolic alkalosis corrected?

A

pCO2 increased

hypoventilation

45
Q

what is the normal anion gap?

A

8-12 mmol/L

46
Q

how is the anion gap calculated?

A

([K+}+{Na+)] - ([Cl-}+{HCO3-}]

47
Q

what does a high anion gap indicate?

A

loss of HCO3- without concurrent increase of Cl-