What is a buffer? (10% of marks) Discuss the body’s buffer systems and how they work.(90% of marks)

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College Answer

Candidates who described an overall view of the body’s buffer systems scored well.
Most candidates could define buffer and could discuss the bicarbonate buffer system; 
however this was not sufficient to pass the question. To pass there had to also be a discussion 
of the other buffer systems including phosphate, protein (haemoglobin, plasma proteins and 
intracellular proteins), ammonia and bone.
Best answers included discussion of open versus closed systems and the relative contribution 
of the differing buffer systems in blood, intracellular fluid, extracellular fluid and urine.