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Hormone

A hormone is a chemical messenger produced by an endocrine gland and carried by blood to target organs.

In one line: Hormone means blood-borne chemical message.

Practice This Concept

Understand it

Hormones help control growth, metabolism, development, and many body functions.
They are released in small amounts, travel through blood, and act only on specific target organs that can respond to them.
Unlike nerve impulses, hormones work more slowly but their effect may last longer.
This makes hormonal control useful for long-term regulation in the body.

Example

Insulin helps control blood sugar level, and thyroxine helps regulate body metabolism.

Rule to remember

Rule: hormone is secreted by an endocrine gland, carried in blood, and acts on a target organ.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

1When blood sugar rises after a meal, the pancreas releases insulin into the blood.
2Insulin reaches body cells and helps lower the blood sugar level.

Method you can reuse

1Identify the gland that releases the hormone.
2Show that the hormone enters blood.
3Name the target organ.
4State the specific action on the body.
5Mention that the response is usually slower but longer lasting.

Visual tip

A flow diagram can show endocrine gland → blood → target organ → response.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why are hormones called chemical messengers rather than nerve signals?

Think first, then show answer

Hormones are called chemical messengers because they are chemicals released by glands and carried by blood to target organs. They do not travel as nerve impulses, and they usually act more slowly than nerve signals.

Common wrong answer

Hormones travel through neurons.

Why it loses marks: Hormones use blood as the transport medium.

Don't mix this up

Students often think hormones travel through nerves like electrical signals. They do not. Hormones travel through blood.

Exam tip

If a question says chemical messenger, blood transport, target organ, or slow action, it is usually asking about hormones.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

Questions may ask for the definition of a hormone, the difference between hormones and nerves, or the role of a particular endocrine gland.

1
Enough for 1 mark
A hormone is a chemical messenger produced by an endocrine gland and carried by blood to target organs.
2
Add for 2 marks
Example: Insulin helps control blood sugar level, and thyroxine helps regulate body metabolism.
3
Add for 3 marks
Hormones help control growth, metabolism, development, and many body functions.

MCQ Quiz

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