1. Acids are hydrogen ion donors and bases are hydrogen ion acceptors. The acid-base balance can be affected by both strong acids and bases that dissociate completely in solution as well as weak acids and bases that only partially dissociate. 2. The pH measures the concentration of hydrogen ions and small changes in pH can significantly impact enzyme function and electrolyte levels. Buffers like bicarbonate and phosphate work to maintain acid-base balance by absorbing or releasing hydrogen ions as conditions change. 3. Respiratory and renal systems help regulate acid-base balance. Respiratory acidosis results from carbon dioxide excess while respiratory alkalosis is due to low carbon dioxide levels. Metabolic acidosis

1. ACID – BASE BALANCE
JOHNY WILBERT, M.Sc[N]
LECTURER,
APOLLO INSTITUTE OF HOSPITAL
MANAGEMENT AND ALLIED SCIENCE

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• Acids are H+ donors.
• Bases are H+ acceptors
• Acids and bases can be:
–Strong – dissociate completely in solution
• HCl
–Weak – dissociate only partially in solution
• Lactic acid, carbonic acid

3. ORGANS INVOLVED IN THE REGULATION OF
A-B-BALANCE

5. pH
• pH is and indirect measure of [H+]

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Small changes in pH can produce major
disturbances
• Most enzymes function only with narrow pH
ranges
• Acid-base balance can also affect electrolytes
(Na+, K+, Cl-)
• Can also affect hormones

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Control of Acids
1. Buffer systems
– Take up H+ or release H+ as conditions
change

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Bicarbonate buffer
• It is present in ECF
• Sodium Bicarbonate (NaHCO3) weak
acid and carbonic acid (H2CO3) weak
base.

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Phosphate buffer
• Major intracellular buffer
• It consist of weak acid (dihydrogen phosphate)
and the base hydrogen phosphate.

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Protein Buffers
• Includes hemoglobin, work in blood.
• Carboxyl group (acid)
• Amino Group (base)

13. Respiratory system - CO2
• Removes co2
• This combines with water to form
carbonic acid.

14. Renal system
• Secretion of hydrogen ions and by the
retention of bicarbonate ions.

15. Disorders of A-B balance
• Acidosis: abnormal condition lowering arterial pH
– before secondary changes in response to the primary aetiological
factor
• Alkalosis: abnormal condition raising arterial pH
– before secondary changes in response to the primary aetiological
factor
• Simple A-B disorders: there is a single primary aetiological
acid-base disorder
• Mixed A-B disorders: more primary aetiological disorders are
present simultaneously
Acidaemia: arterial pH<7.36 (i.e. [H+]>44 nM)
Alkalaemia: arterial pH>7.44 (i.e. [H+]<36 nM)

16. TYPES
• Respiratory acidosis and alkalosis
• Metabolic acidosis and alkalosis

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Respiratory Acidosis
• Carbonic acid excess
• Hypercapnia – high levels of CO2 in
blood

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Treatment of Respiratory Acidosis
• Airway clearance
• Restore ventilation by 02 or ventilator
• Bronchodilators
• Treat underlying dysfunction or disease

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Respiratory Alkalosis
• Carbonic acid deficit
• pCO2 less (hypocapnea)

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Treatment of Respiratory Alkalosis
• Treat underlying cause
• Breathe into a paper bag
• Pursued lip breathing or breathing through 1
nostril

21. METABOLIC ALKALOSIS:
Is a condition in which the pH of tissue is
elevated beyond the normal range.
METABOLIC ACIDOSIS:
Is a condition in which the pH of tissue is
decreased beyond the normal range.

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25. Thank you