Book a tutor
SearchResourcesRevision notesFlashcardsMind mapsExam questionsTopic testsPracticalsGCSE Biology coursesAQA GCSE Biology (8461)AQA GCSE Combined Science: Trilogy (8464)Edexcel GCSE Biology (1BI0)Edexcel GCSE Combined Science (1SC0)IGCSE Biology coursesCambridge IGCSE Biology (0610)Cambridge IGCSE Combined Science (0653)Edexcel International GCSE Biology (4BI1)Edexcel International GCSE Science (Double Award) (4SD0)MoreAboutContactBook a tutor

Control of blood glucose concentration

Homeostasis and response · Hormonal coordination in humans · note 2 of 11

Spec 4.5.3.2Download all Hormonal coordination in humans notes (PDF)Download all notes (PDF)12 pages

Control of blood glucose concentrationSpec 4.5.3.2

In short

Blood glucose concentration is monitored and controlled by the pancreas. If the concentration is too high, the pancreas produces the hormone insulin, which causes glucose to move from the blood into the cells. In liver and muscle cells, excess glucose is converted to glycogen for storage, so the blood glucose concentration falls back to the normal level.

Blood glucose concentration is monitored and controlled by the pancreas.

If the blood glucose concentration is too high, the pancreas produces the hormone insulin. Insulin causes glucose to move from the blood into the cells. In liver and muscle cells excess glucose is converted to glycogen for storage.

  1. Blood glucose concentration rises (for example after a meal).
  2. The pancreas detects this and produces insulin.
  3. Insulin causes glucose to move from the blood into the cells.
  4. In the liver and muscle cells, excess glucose is converted to glycogen.
  5. Blood glucose concentration falls back to the normal level.
Higher tier (what this means)Higher tier: only on the Higher tier papers. Foundation students can skip it. What the labels mean

Glucagon and negative feedback

Higher tier (what this means)Higher tier: only on the Higher tier papers. Foundation students can skip it. What the labels mean

If the blood glucose concentration is too low, the pancreas produces the hormone glucagon. Glucagon causes glycogen to be converted into glucose and released into the blood.

Higher tier (what this means)Higher tier: only on the Higher tier papers. Foundation students can skip it. What the labels mean

Insulin and glucagon work against each other in a negative feedback cycle. When one hormone brings the glucose level back to normal, the pancreas stops releasing it. This keeps blood glucose near the normal level.

Higher tier (what this means)Higher tier: only on the Higher tier papers. Foundation students can skip it. What the labels mean
Insulin and glucagon
InsulinGlucagon
Released when blood glucose isToo highToo low
Effect on glucoseGlucose moves from blood into cellsGlycogen is converted into glucose and released into the blood
Effect on blood glucoseFallsRises
Negative feedback loop for blood glucose: when glucose is too high the pancreas releases insulin and glucose moves into cells, so glucose falls back to normal; when glucose is too low the pancreas releases glucagon and glycogen is converted into glucose, so glucose rises back to normal. (opens full size in a new tab)
Insulin and glucagon keep blood glucose near normal by negative feedback.
Common mistake:

Do not mix up glucose, glycogen and glucagon. Glucose is the sugar, glycogen is the storage carbohydrate, and glucagon is the hormone.

Written and checked against the AQA GCSE Biology (8461) specification · Updated October 2026

Frequently asked questions

What does insulin do to blood sugar?

Insulin lowers blood sugar (blood glucose concentration). The pancreas produces insulin when blood glucose is too high, for example after a meal. Insulin causes glucose to move from the blood into the cells, and in liver and muscle cells excess glucose is converted to glycogen for storage. Blood glucose then falls back to the normal level.

What is the difference between insulin and glucagon?

Higher tier Insulin lowers blood glucose and glucagon raises it. Both are made by the pancreas. Insulin is released when blood glucose is too high and makes glucose move from the blood into cells. Glucagon is released when it is too low and causes glycogen to be converted into glucose and released into the blood. They work in a negative feedback cycle.

Why are hormones called chemical messengers?

Hormones are called chemical messengers because they are chemicals secreted by glands directly into the bloodstream, which carries them to a target organ where they produce an effect. Compared with nerve impulses, hormones act more slowly but their effects last longer. They reach every part of the body but only affect their target organ.

All 5 questions on Hormonal coordination in humans