ACID/BASE%20BALANCE

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ACID/BASE BALANCE

• D. C. Mikulecky

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ACIDS, BASES AND SALTS

• CHEMICAL COMPOUNDS CAN BE PROTON DONORS OR
  ACCEPTORS
• PROTON DONORS ARE ACIDS
• PROTON ACCEPTORS ARE BASES
• ACIDS AND BASES REACT TO NEUTRALIZE EACH OTHER
  FORMING SALTS

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ACID/BASE REACTIONS
HCl NaOH NaCl H2O
ACID BASE SALT WATER
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ACID/BASE BALANCE AND THE BLOOD
OH -
H
Acidic
Alkaline (Basic)
Neutral
pH
7
0
14
Arterial Blood
Venous Blood
Acidosis
Alkalosis
DEATH
7.4
DEATH
Normal 7.35-7.45
8.0
6.8
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CHEMICAL BUFFER SYSTEMS
Unbuffered Salt Solution
All protons are free
Add HCl
H Cl-
Na Cl-
Na Cl-
Protons taken up as Carbonic Acid
H2CO3 HCO3- Buffer
Add HCl
H2CO3 HCO3- H
H2CO3 HCO3- H
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CHEMICAL BUFFER SYSTEMS

• Weak acid/salt systems act as a sponge for
  protons
• As acidity tends to increase they take protons up
• As acidity tends to decrease they release protons

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CHEMICAL BUFFER SYSTEMS

• Carbonic acid/Bicarbonate Primary buffer against
  non-carbonic acid changes
• Proteins Primary ICF buffer, also ECF
• Hemoglobin Primary buffer against carbonic acid
  changes
• Phosphate Urinary buffer, also ICF

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ROLE OF RESPIRATORY SYSTEM IN ACID/BASE BALANCE

• Alterations in ventilation alter the rate of
  excretion of carbon dioxide
• Alterations in the rate of carbon dioxide
  excretion cause alterations in pH through
  carbonic acid
• This way the respiratory system can help control
  non-respiratory acidosis and alkalosis

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Sources of acidosis

• Metabolic Severe diarrhea, Diabetes mellitus,
  strenuous exercise, uremia
• Respiratory hypoventilation

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Sources of alkalosis

• Metabolic Vomiting, ingestion of alkaline drugs
• Respiratory hyperventilation

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Renal regulation of blood acidity

• Proton excretion
• Bicarbonate excretion
• Ammonia secretion