A person eats a large meal containing a high amount of carbohydrates. Explain how the endocrine system responds to restore normal blood glucose levels, including the role of the effector and the type of feedback system involved.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Blood glucose concentration rises significantly above the normal level after a person consumes a large carbohydrate-rich meal.
Model answer (4 marks)
The pancreas senses the high glucose level and releases insulin into the blood.
Insulin acts on cells and the liver, signalling them to take up glucose and store it as glycogen, which lowers the blood glucose concentration.
The pancreas itself is the effector gland, producing the hormone that restores the normal level.
This is a negative‑feedback system, as the rise in glucose triggers a response that opposes and reverses the stimulus.
Insulin acts on cells and the liver, signalling them to take up glucose and store it as glycogen, which lowers the blood glucose concentration.
The pancreas itself is the effector gland, producing the hormone that restores the normal level.
This is a negative‑feedback system, as the rise in glucose triggers a response that opposes and reverses the stimulus.
Examiner tips
- Use the word ‘insulin’ and ‘pancreas’ – examiners expect these terms. Show the sequence: detection → hormone release → action on target → return to normal. Mention ‘negative feedback’ explicitly.
- Include the effector gland (pancreas) – this is a key point in the mark scheme.
Common mistakes
- Confusing insulin with glucagon or vice‑versa. Omitting the pancreas as the effector gland. Calling the system positive feedback instead of negative.
Mark scheme (4 marks)
- The pancreas detects the rise in blood glucose and secretes insulin into the bloodstream
- Insulin causes cells / the liver to absorb glucose and convert it to glycogen, lowering blood glucose concentration
- The pancreas acts as the effector, as it is the gland that produces the response to restore optimum conditions
- This is a negative feedback system because it reverses/opposes the initial stimulus (rise in blood glucose)
Key terms in this question
Related
- Revision notes: Maintaining internal environments →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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