Who this is for: Cambridge IGCSE Coordinated Science (0654) students who want hormones — endocrine glands, adrenaline and blood glucose control — to become reliable marks instead of a list they confuse with the nervous system.
What query it owns: how to understand and revise hormones in Cambridge IGCSE Coordinated Science.
Why this is safe: this page owns the hormones revision-guide angle, while Tutopiya’s Hormones subtopic page owns the learning resource and the free Hormones quiz owns the practice.

Hormones are chemical messengers secreted by endocrine glands into the blood, travelling to target organs where they bring about a response. Cambridge IGCSE Coordinated Science (0654) tests whether you can name key hormones, state their source and effect, and compare hormonal with nervous coordination. This guide covers the syllabus hormones, the adrenaline response, and the question types that appear every year.

Key takeaways

• Hormones are chemical messengers carried in the blood to target organs.
• Hormonal coordination is slower but longer-lasting than the nervous system.
• Adrenaline prepares the body for fight or flight (increased heart rate, breathing, blood to muscles).
• Insulin lowers blood glucose; glucagon raises it — both from the pancreas.
• Exam answers must state gland, hormone and effect together.

What are hormones in Cambridge IGCSE Coordinated Science?

Hormones are chemicals produced by endocrine glands, released directly into the bloodstream, and carried to specific target organs where they cause a response. Unlike nerve impulses, hormones act more slowly but have longer-lasting effects. Key examples include adrenaline (adrenal glands), insulin and glucagon (pancreas).

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

The core ideas you must master

Idea	What it means	How the exam uses it
Endocrine gland	Ductless gland secreting hormones into blood	”Name the gland that produces insulin”
Target organ	Organ with receptors for a specific hormone	”State the target organ of adrenaline”
Adrenaline response	Fight-or-flight preparation	”Describe the effects of adrenaline”
Blood glucose control	Insulin lowers, glucagon raises	”Explain how blood glucose is regulated”
Nervous vs hormonal	Speed, duration, pathway differences	”Compare nervous and hormonal coordination”

Key hormones you must know

Hormone	Gland	Effect
Adrenaline	Adrenal glands	Increases heart rate, breathing rate, blood flow to muscles; prepares for danger
Insulin	Pancreas	Lowers blood glucose (converts glucose to glycogen in liver)
Glucagon	Pancreas	Raises blood glucose (converts glycogen to glucose in liver)

Nervous vs hormonal coordination

Feature	Nervous system	Hormonal system
Signal type	Electrical impulses	Chemical hormones
Pathway	Neurones	Bloodstream
Speed	Very fast	Slower
Duration	Short-lived	Longer-lasting
Target	Specific muscles/glands	Target organs with receptors

Hormones in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical hormone stem
Define	Precise syllabus definition	”Define a hormone.”
State	Short factual answer	”State the gland that secretes adrenaline.”
Describe	Effects step by step	”Describe the effects of adrenaline on the body.”
Explain	Cause and effect	”Explain how insulin controls blood glucose.”
Compare	Similarities and differences	”Compare nervous and hormonal coordination.”

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

1. “Define a hormone.” A hormone is a chemical substance produced by an endocrine gland, transported in the blood, that acts on a target organ. Mark-scheme reward: chemical, endocrine gland, blood, target organ.
2. “Describe the effects of adrenaline on the body.” Increases heart rate, increases breathing rate, diverts blood to muscles, increases blood glucose — prepares body for fight or flight. Reward: named effects linked to danger response.
3. “Explain how insulin controls blood glucose.” When blood glucose is high, pancreas releases insulin → liver converts glucose to glycogen → blood glucose decreases. Reward: trigger + mechanism + result.

When you can recognise the wording instantly, work the full set on the Hormones quiz to lock the hormone table in.

How hormones connect to the rest of the syllabus

Hormones link to Nervous Control In Humans (compare coordination methods) and Homeostasis (insulin and glucagon in blood glucose control). Tropic Responses covers plant hormones (auxin). The Cambridge IGCSE Coordinated Science resource hub links every Coordination and Response subtopic.

Common mistakes students make

• Confusing insulin (lowers glucose) with glucagon (raises glucose).
• Saying hormones travel along neurones (they travel in the blood).
• Forgetting target organ in hormone definitions.
• Omitting fight or flight context for adrenaline.
• Mixing up endocrine (ductless) with exocrine (with ducts) glands.

When you need more support

If hormone questions keep costing marks — especially insulin vs glucagon — work through the Hormones quiz, then get focused help from a Cambridge IGCSE Coordinated Science tutor.

Frequently asked questions

Is hormones hard in Cambridge IGCSE Coordinated Science? The hormone table is small and learnable, but marks are lost when students confuse insulin with glucagon or omit target organs.

What is the difference between nervous and hormonal coordination? Nervous coordination uses fast electrical impulses along neurones; hormonal coordination uses slower chemical messengers in the blood with longer-lasting effects.

Which gland produces adrenaline? The adrenal glands.

How do I revise hormones effectively? Learn the hormone table (gland, hormone, effect), compare with nervous coordination, then take the Hormones quiz.

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

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