Who this is for: Cambridge IGCSE Coordinated Science (0654) students who want homeostasis — negative feedback, blood glucose and body temperature — to become reliable marks instead of a definition they cannot apply.
What query it owns: how to understand and revise homeostasis in Cambridge IGCSE Coordinated Science.
Why this is safe: this page owns the homeostasis revision-guide angle, while Tutopiya’s Homeostasis subtopic page owns the learning resource and the free Homeostasis quiz owns the practice.

Homeostasis is the maintenance of a constant internal environment despite changes in external conditions. Cambridge IGCSE Coordinated Science (0654) focuses on negative feedback controlling blood glucose and body temperature. This guide covers the syllabus definitions, feedback loops, and the question types that appear every year.

Key takeaways

• Homeostasis keeps internal conditions stable (e.g. blood glucose, body temperature).
• Negative feedback reverses a change — detects deviation, triggers a corrective response, returns to normal.
• Insulin lowers blood glucose; glucagon raises it — classic negative feedback loop.
• Body temperature is controlled by sweating, shivering, hair erection and blood-vessel diameter changes.
• Exam answers must describe the full feedback loop, not just name hormones.

What is homeostasis in Cambridge IGCSE Coordinated Science?

Homeostasis is the maintenance of a constant internal environment. The body monitors conditions such as blood glucose concentration and core body temperature, detects changes from the set point, and uses negative feedback to bring levels back to normal. Hormones (insulin, glucagon) and nervous responses (sweating, shivering) are the main mechanisms tested.

You can read the full explanation, worked examples and notes on Tutopiya’s Homeostasis subtopic page before you attempt questions.

The core ideas you must master

Idea	What it means	How the exam uses it
Constant internal environment	Stable conditions inside the body	”Define homeostasis”
Negative feedback	Response reverses the detected change	”Explain the role of negative feedback”
Blood glucose control	Insulin and glucagon from pancreas	”Describe control of blood glucose”
Temperature control	Mechanisms to lose or gain heat	”Describe how the body cools down”
Set point	Normal level the body maintains	”State what happens when temperature rises”

Blood glucose control — negative feedback step by step

The safest method works for every blood glucose explain question.

1. Detect — pancreas monitors blood glucose concentration.
2. Compare — level is compared to the set point (normal range).
3. If too high — pancreas releases insulin → liver converts glucose to glycogen → blood glucose decreases.
4. If too low — pancreas releases glucagon → liver converts glycogen to glucose → blood glucose increases.
5. Return to normal — negative feedback reverses the change until the set point is restored.

Once you have worked through the loop a few times, test yourself with the free Homeostasis quiz — it tells you fast whether the feedback sequence has actually stuck.

Body temperature control

Condition	Mechanism	Effect
Too hot	Sweating (evaporation cools skin)	Heat loss
Too hot	Vasodilation (blood vessels widen near skin)	More heat radiated
Too cold	Shivering (muscle contractions)	Heat generated
Too cold	Vasoconstriction (blood vessels narrow)	Less heat lost from skin
Too cold	Hair erection (traps insulating air layer)	Reduced heat loss

Homeostasis in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical homeostasis stem
Define	Precise syllabus definition	”Define the term homeostasis.”
Explain	Cause and effect / feedback loop	”Explain how negative feedback controls blood glucose.”
Describe	Step-by-step mechanism	”Describe how the body responds when temperature rises.”
State	Short factual answer	”State the hormone that lowers blood glucose.”
Suggest	Apply to new context	”Suggest why a diabetic person needs insulin injections.”

Worked exam-style stems (how to answer the wording)

1. “Define the term homeostasis.” Homeostasis is the maintenance of a constant internal environment. Mark-scheme reward: constant/internal environment.
2. “Explain how negative feedback controls blood glucose.” When glucose is high, insulin is released → glucose converted to glycogen → level falls. When glucose is low, glucagon is released → glycogen converted to glucose → level rises. The response reverses the change. Reward: both directions + reversal.
3. “Describe how the body responds when core temperature rises.” Sweating increases (evaporation cools), blood vessels vasodilate near skin (more heat radiated), hairs lie flat. Reward: named mechanism + heat loss linked.

When you can recognise the wording instantly, work the full set on the Homeostasis quiz to lock the feedback loops in.

How homeostasis connects to the rest of the syllabus

Homeostasis links to Hormones (insulin and glucagon) and Nervous Control In Humans (temperature responses). Respiration releases energy used to maintain body temperature. The Cambridge IGCSE Coordinated Science resource hub links every Coordination and Response subtopic.

Common mistakes students make

• Defining homeostasis without constant internal environment.
• Confusing insulin and glucagon actions.
• Describing only one direction of the blood glucose feedback loop.
• Saying positive feedback when negative feedback is required.
• Forgetting vasodilation/vasoconstriction in temperature questions.

When you need more support

If homeostasis questions keep costing marks — especially negative feedback loops — work through the Homeostasis quiz, then get focused help from a Cambridge IGCSE Coordinated Science tutor.

Frequently asked questions

Is homeostasis hard in Cambridge IGCSE Coordinated Science? The definition is simple, but marks are lost when students cannot describe the full negative feedback loop for blood glucose or temperature.

What is negative feedback? A control mechanism where a change triggers a response that reverses the change, returning conditions to normal.

Which hormone lowers blood glucose? Insulin, secreted by the pancreas when blood glucose is too high.

How do I revise homeostasis effectively? Draw feedback loops for blood glucose and temperature, learn insulin vs glucagon, then take the Homeostasis quiz.

Ready to master Cambridge IGCSE Coordinated Science homeostasis?

Start with the Homeostasis subtopic page, then book a free trial with a Cambridge IGCSE Coordinated Science specialist to turn homeostasis into guaranteed marks.

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