Explain how the endocrine system controls blood glucose concentration when a student eats a large meal containing a high amount of carbohydrates.

OCR GCSE Biology A: Gateway Science (J247) — B3.2 Coordination and control — the endocrine system · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

After eating a large meal rich in carbohydrates, a student's blood glucose concentration rises above the optimum level. The endocrine system works to restore normal blood glucose levels.

Model answer (4 marks)

After a carbohydrate‑rich meal the blood glucose level rises. The pancreas senses this increase and secretes insulin into the bloodstream. Insulin promotes the uptake of glucose by cells and its conversion into glycogen for storage. This negative feedback loop lowers the blood glucose concentration back to the optimum level.

Examiner tips

Use the word ‘secretes’ for insulin, not ‘produces’.
Show the sequence: rise → detection → insulin release → glycogen synthesis → return to normal.
Mention ‘negative feedback’ to link the response to the initial change.

Common mistakes

Confusing insulin with glucagon or omitting the pancreas as the detector.
Failing to state that insulin causes glycogen synthesis.
Not identifying the process as negative feedback.

Mark scheme (4 marks)

The rise in blood glucose concentration is detected by the pancreas
The pancreas secretes/releases insulin into the bloodstream
Insulin causes glucose to be converted into glycogen (for storage)
This is an example of negative feedback, as the response reverses the initial rise, restoring blood glucose concentration to the optimum level

Key terms in this question

endocrine system

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