How do hormones coordinate the body, and how is blood glucose controlled?
The endocrine system and hormones, the control of blood glucose by insulin and glucagon, type 1 and type 2 diabetes, and the principle of homeostasis with negative feedback.
A focused answer to Edexcel GCSE Combined Science Topic 7 (CB7), covering the endocrine system and hormones, the control of blood glucose by insulin and glucagon, type 1 and type 2 diabetes, and the principle of homeostasis with negative feedback.
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What this dot point is asking
Edexcel wants you to describe the endocrine system and how hormones work, explain how blood glucose concentration is controlled by insulin and glucagon, compare type 1 and type 2 diabetes, and explain homeostasis using the idea of negative feedback.
The endocrine system and hormones
Key glands include the pancreas (insulin and glucagon), the thyroid (thyroxine, which controls the metabolic rate), the adrenal glands (adrenaline, released in fear or stress to prepare the body for action), and the reproductive organs. The pituitary gland in the brain is the master gland that controls others by releasing hormones that act on them.
Because hormones travel in the blood, they reach every part of the body, but only the target organs with the right receptors respond. This is why a single hormone can coordinate a response in several places at once, unlike a nervous impulse, which is sent to one precise location.
Homeostasis and negative feedback
Controlling blood glucose
Blood glucose concentration must be kept within narrow limits, controlled by the pancreas.
- When blood glucose is too high (after a meal): the pancreas releases insulin. Insulin makes liver and muscle cells take up glucose, and the liver stores the excess as glycogen. Blood glucose falls.
- When blood glucose is too low (after exercise or fasting): the pancreas releases glucagon. Glucagon makes the liver break down glycogen back into glucose and release it. Blood glucose rises.
These two hormones work as a negative-feedback loop that keeps glucose near a set point.
Diabetes
Worked example
Try this
Q1. Name the gland that controls blood glucose. [1 mark]
- Cue. The pancreas.
Q2. State the cause of type 1 diabetes. [1 mark]
- Cue. The pancreas does not produce enough insulin.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20195 marksExplain how the body reduces the concentration of glucose in the blood after a meal, including the role of the pancreas, insulin and the liver.Show worked answer →
A 5-mark explain question on blood glucose control.
After a meal, the blood glucose concentration rises (1 mark). The pancreas detects this and releases the hormone insulin into the blood (1 mark). Insulin travels to the liver and muscle cells and causes them to take up glucose from the blood (1 mark). The liver converts the excess glucose into glycogen for storage (1 mark). As a result, the blood glucose concentration falls back to normal (1 mark).
Markers reward the rise being detected by the pancreas, insulin release, glucose uptake by cells, conversion to glycogen, and the return to normal. This is the standard negative-feedback answer.
Edexcel 20214 marksCompare type 1 and type 2 diabetes in terms of their cause and treatment.Show worked answer →
A 4-mark compare question.
In type 1 diabetes the pancreas does not produce enough insulin (often starting in childhood), whereas in type 2 diabetes the body cells stop responding properly to insulin (often linked to obesity and later in life) (2 marks). Type 1 is treated with insulin injections, whereas type 2 is usually controlled by a carbohydrate-controlled diet, exercise and weight loss, sometimes with medication (2 marks).
Markers reward the cause difference (no insulin versus cells not responding) and the treatment difference (injections versus diet and lifestyle).
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Sources & how we know this
- Edexcel GCSE (9-1) Combined Science (1SC0) specification — Pearson (2016)