Outline the distribution of calcium in normal plasma (20% of marks).

Describe the hormonal control of the calcium concentration in the plasma (80% of marks).

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College Answer

As stated in the question, the distribution in plasma (not body) was expected. Candidates are 
reminded to include units [mmol/l]. 
Many candidates spent considerable effort describing the roles of calcium and particularly its 
role in excitation contraction coupling – which was not asked and hence scored no marks.
It was expected that candidates were able to identify the roles of parathormone (PTH), 1,25 
OH vitamin D and calcitonin as the major hormonal regulators. Better answers were able to 
describe the physiology and integration of these hormones at the gut, kidney and bone. 
Calcitonin and its transient and (probable) minor opposite role were also identified in these 
answers.
Better answers were also able to identify the permissive roles of growth hormone, cortisol and 
thyroxine.