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Notes
      3. Old stuff
          3.2. Old physio stuff (around 2005)
              3.2.3. Physiology
                  3.2.3.1. Acid and base
                      3.2.3.1.2. Defence to acid-base disturbance
 3.2.3.1.2.1. Buffer 
 1. Contribution by buffering systems
 2. pKa

Buffer

[Ref: KB's online acid-base text]

A buffer is a solution containing substances which have the ability to minimise changes in pH when an acid or base is added to it.

 

Major body buffer systems

ISF

  • HCO3
    * Important for metabolic acid

NB:

  • Phosphate and protein concentration too low

Blood

  • HCO3
    * Important for metabolic acid
  • Hb
    * Important for CO2
  • Plasma protein
    * Minor

NB:

  • Phosphate concentration too low

Intracellular fluid

  • Protein
    * Important buffer
  • Phosphate
    * Important buffer

Urine

  • Phosphate
    * Most of the titratable acid
  • Ammonia
    * Formation of NH4+

Bone

  • Calcium carbonate
    * Important in prolonged metabolic acidosis

 

Bicarbonate buffering system

Most important buffering system

Contributes 80% of buffering in ECF

Buffers metabolic acidosis
* But cannot buffer respiratory acidosis

 

 

 

 

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