ChemPath: Acid-Base Handling Flashcards

1
Q

What is the normal range for H+ concentration?

A

35-45 mmol/L in ECF

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

What equation links H+ concentration to pH?

A

pH = log1/[H+]

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

What are the three main physiological buffers?

A
  • Bicarbonate
  • Haemoglobin
  • Phosphate

NOTE: also protein and bone

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

What is the rate of production of H+ ions per day?

A

50 - 100 mmol/day

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

Describe how the kidneys excrete H+ ions.

A

Bicarbonate is regenerated through the production of carbonic acid

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

Describe how H+ ions pass through the renal epithelial membrane.

A

H+ ions cannot pass through the membrane itself so a transport system is necessary (Na+/H+ exchange)

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

What is the rate of production of carbon dioxide per day?

A

20,000-25,000 mmol/day

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

Describe the respirtaory control over carbon dioxide.

A
  • Respiratory is controlled by chemoreceptors in the hypothalamic respiratory centre
  • An increase in CO2 will stimulate an increase in ventilation which then brings down CO2 concentration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What information is provided by ABGs?

A
  • pO2
  • pCO2
  • pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the primary abnormality in metabolic acidosis? List three causes with examples.

A

Primary abnormality is increased H+ (with decreased bicarbonate)

Caused by:

  • Increased H+ production (e.g. DKA)
  • Decreased H+ excretion (e.g. renal tubular acidosis)
  • Bicarbonate loss (e.g. intestinal fistula)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the primary abnormality in respiratory acidosis? List three causes with examples.

A

Primary abnormality is increased CO2 (therefore, increased H+) and a slight increase in bicarbonate

Caused by:

  • Decreased ventilation
  • Poor lung perfusion
  • Impaired gas exchange

NOTE: metabolic compensation is slower than respiratory compensation

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

What is the primary abnormality in metabolic alkalosis? List three causes.

A

Primary abnormality is decreased H+ (with increased bicarbonate)

Caused by:

  • H+ loss (e.g. pyloric stenosis)
  • Hypokalaemia
  • Ingestion of bicarbonate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the primary abnormality in respiratory alkalosis? List three causes.

A

Primary abnormality is reduced CO2

If prolonged, this can lead to reduced renal H+ excretion and reduced bicarbonate generation

Can be caused by hyperventilation due to:

  • Voluntary
  • Artificial ventilation
  • Stimulation of the respiratory centre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What derangement of acid-base balance would be caused by pyloric stenosis?

A

Metabolic alkalosis due to loss of H+ from profuse vomiting

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

Which condition classically causes a mixed respiratory alkalosis and metabolic acidosis?

A
  • Aspirin overdose
  • Aspirin stimulates ventilation and reduces renal excretion of H+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly