Example 1
Glucose rises from 4.8 to 7.3 mmol/L. Calculate the increase.
7.3−4.8=2.5 mmol/L. The rise would normally favour insulin secretion.
Year 12 · SACE Stage 2
Blood glucose regulation
Match insulin and glucagon actions and interpret glucose data.
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Method and worked examples
Blood glucose concentration is regulated within a suitable range. Rising glucose stimulates pancreatic beta cells to release insulin. Insulin promotes glucose uptake in responsive tissues and storage processes including glycogen formation. As glucose falls, the stimulus for insulin secretion decreases. Glucose control involves several tissues rather than the pancreas physically storing every glucose molecule.
Falling glucose stimulates pancreatic alpha cells to release glucagon, which promotes liver glucose release, including through glycogen breakdown. The two hormones therefore support opposing responses in a negative-feedback system. Diabetes mellitus involves persistent difficulty regulating glucose because of insufficient insulin production, impaired tissue responsiveness or both. A supplied glucose curve can show a higher level or slower return, but a practice graph alone does not establish a medical diagnosis. Always use the units and conditions given.
Example 1
Example 2
A curve peaks at 8 mmol/L and later returns to 5 mmol/L. What is the peak-to-final decrease?
8−5=3 mmol/L. This is a concentration change, not a percentage unless a denominator is specified.
Watch out: Glucagon is a hormone. Glycogen is a carbohydrate storage molecule.