Exocrine and Endocrine Glands, Hormones, and the Thyroid, Adrenal, Pancreas and Pituitary (ICSE Class 8)
Updated 17 October 2026 · Fact-checked
Exocrine glands release their secretions through ducts, while endocrine glands are ductless and pour hormones straight into the blood. A hormone is a chemical messenger made by an endocrine gland that acts on a target organ. The thyroid secretes thyroxine, the adrenals adrenaline, the pancreas insulin and the pituitary growth hormone and controlling hormones.
Exocrine glands use a duct to deliver secretions; endocrine glands have no duct and release hormones into the blood to reach a target organ.
Illustration drawn for QuestionBuddy.
Understand Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands
Gland. An organ or group of cells that makes and releases a useful substance.
| Exocrine glands | Endocrine glands | |
|---|---|---|
| Ducts | have ducts | ductless |
| Secretion goes | through the duct to a particular place | directly into the blood |
| Product | enzymes, saliva, sweat, tears | hormones |
| Examples | salivary, sweat, tear glands | thyroid, adrenal, pituitary |
The pancreas is both: it sends pancreatic juice through a duct (exocrine) and its islets of Langerhans release insulin into the blood (endocrine).
Hormone. A chemical messenger secreted by an endocrine gland directly into the blood, which carries it to a target organ. Hormones work in very small amounts, act more slowly than nerves but usually last longer. Too much (hypersecretion) or too little (hyposecretion) causes disorders.
The four glands (syllabus table).
| Gland | Location | Secretion | Function |
|---|---|---|---|
| Pituitary | base of the brain, pea-sized | growth hormone and hormones that control other glands | growth of bones and muscles; controls thyroid, adrenals, testes, ovaries; master gland |
| Thyroid | neck, in front of the windpipe, butterfly-shaped | thyroxine | controls metabolism; needed for normal growth |
| Adrenal (pair) | on top of each kidney | adrenaline | emergency hormone: faster heart rate and breathing, more sugar in blood, 'fight or flight' |
| Pancreas (islets) | abdomen, behind the stomach | insulin (and glucagon) | insulin lowers blood sugar; glucagon raises it |
Disorders.
- Goitre: swollen neck due to lack of iodine in the diet (thyroxine contains iodine); prevented by iodised salt.
- Diabetes mellitus: too little insulin, so blood sugar stays high and sugar appears in urine; managed by diet, exercise and, if needed, insulin injections.
- Gigantism: too much growth hormone in childhood. Dwarfism: too little.
Nervous and hormonal control compared.
| Nerves | Hormones |
|---|---|
| electrical impulses | chemicals in blood |
| very fast, short-lived | slower, longer-lasting |
Position order (head to abdomen). Pituitary → thyroid → adrenals → pancreas.
Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands: key facts
- Glands
Exocrine ducts, enzymes Endocrine ductless, hormones into blood Pancreas both - Hormones travel in blood.
- Gland table
Pituitary growth hormone, master gland Thyroid thyroxine, metabolism Adrenal adrenaline, emergency Pancreas insulin, blood sugar - Location: brain, neck, kidneys, abdomen.
- Disorders
Goitre iodine lack, thyroid Diabetes low insulin Gigantism excess growth hormone - Hyposecretion or hypersecretion.
How to answer Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands questions
Expect: define hormone, differentiate exocrine and endocrine, complete a table of the four glands, or link a disorder to the gland and hormone.
- 1Check for ducts: with a duct it is exocrine; ductless means endocrine.
- 2Name the hormone, the gland and the target effect in a single line.
- 3Fill tables in head-to-abdomen order: pituitary, thyroid, adrenals, pancreas.
- 4For disorders, say which hormone is too much or too little and the effect.
- 5For comparisons, give at least two points for each side.
Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands in real life
The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.
Heart pounding before a race
Suppose a boy standing at the start line of a race feels his heart thump and his breathing quicken, although he has not yet moved.
Which gland and hormone are involved, and what does the body gain?
Try it first, then show the solutionSolution
- The adrenal glands release adrenaline into the blood.
- Heart rate and breathing rise, and more sugar and blood go to muscles.
- His body is ready to run fast.
Answer: Adrenal glands release adrenaline, preparing the body for an emergency.
Memory hook: Adrenaline = fight or flight.
Iodised salt
Suppose in a hilly village where the diet lacks iodine many adults have swollen necks, and a health worker advises iodised salt.
Explain the condition and why the advice helps.
Try it first, then show the solutionSolution
- Thyroxine contains iodine, so lack of iodine reduces its production.
- The thyroid gland enlarges, causing a swelling called goitre.
- Iodised salt supplies the iodine needed.
Answer: Goitre is caused by iodine deficiency; iodised salt gives the thyroid the iodine it needs.
Memory hook: No iodine, big neck.
Tricks to remember Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands
Short memory aids. Say each one aloud once, then use it on a question the same day.
Ductless = delivers to blood
Endo = inside the blood; exo = outside through a tube.
Use it when: Gland types.
PTAP
Pituitary, Thyroid, Adrenal, Pancreas: top to bottom.
Use it when: Location table.
Insulin lets sugar in
Insulin invites glucose into cells.
Use it when: Blood sugar questions.
Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands: solved examples
Ordered from board level to HOTS. Try each one before you open the solution.
Example 1: Ductless gland · 1 mark · MCQBoard level
Which one is an endocrine gland?
(a) salivary gland (b) sweat gland (c) thyroid (d) tear gland
Try it first, then show the solutionSolution
- The thyroid is ductless and secretes thyroxine.
Answer: (c).
Example 2: Features of hormones · 2 marks · Short answerBoard level
State two features of hormones and the kind of gland that makes them.
Try it first, then show the solutionSolution
- They act in very small amounts, and are carried in the blood to target organs (any two features) (1 mark).
- They are made by endocrine (ductless) glands (1 mark).
Answer: Tiny amounts, carried by blood to target organs; endocrine glands.
Example 3: Table rows · 4 marks · Long answerHarder board level
Write, in the form of a table, the location, secretion and one function of (a) the thyroid and (b) the pituitary, and explain why the pituitary is called the master gland.
Try it first, then show the solutionSolution
- Thyroid: neck in front of the windpipe; thyroxine; controls metabolism (1 mark).
- Pituitary: base of the brain; growth hormone and controlling hormones; growth of bones and muscles (1 mark).
- The pituitary secretes hormones that control the working of other endocrine glands (thyroid, adrenals, testes, ovaries) (1 mark).
- Hence a fault in the pituitary can upset several glands at once (1 mark).
Answer: Thyroid: neck, thyroxine; pituitary: brain, growth hormone; it controls other glands.
Example 4: Two hormones, one sugar · 3 marks · Short answerHarder board level
After a meal a person's blood sugar rises; hours later it falls. Name the two pancreatic hormones, say what each does and how the body returns blood sugar to normal after the meal.
Try it first, then show the solutionSolution
- Insulin lowers blood sugar, as cells take up glucose and the liver stores extra as glycogen (1 mark).
- Glucagon raises blood sugar when it falls (1 mark).
- After the meal, insulin acts and brings the level back to normal (1 mark).
Answer: Insulin lowers; glucagon raises; insulin restores normal after a meal.
Example 5: Tall at twelve · 4 marks · Case-basedHOTS / competency
A 12-year-old boy is much taller than others and still growing fast, while his thyroid works normally. (a) Name the likely gland and hormone. (b) Name the condition. (c) Name the condition if the same hormone were deficient in childhood. (d) Why is that gland called the master gland?
Try it first, then show the solutionSolution
- (a) Pituitary gland; growth hormone (1 mark).
- (b) Gigantism (1 mark).
- (c) Dwarfism (1 mark).
- (d) Its hormones control the working of other endocrine glands (1 mark).
Answer: Pituitary and growth hormone; gigantism; dwarfism; master gland controls others.
Where students lose marks in Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands
The slips examiners see most often, and what to write instead.
Mistake: Saying hormones travel through ducts
Exocrine and endocrine are mixed up.
Do this: Endocrine glands are ductless and release hormones into blood.
Usually costs: 1 mark.
Mistake: Wrong location of glands
Adrenals are placed in the neck or the pancreas on the brain.
Do this: Pituitary in the brain, thyroid in the neck, adrenals on the kidneys, pancreas behind the stomach.
Usually costs: 1 mark.
Mistake: Insulin raises blood sugar
Insulin and glucagon swapped.
Do this: Insulin lowers; glucagon raises.
Usually costs: 1 mark.
Mistake: Not calling the pancreas a mixed gland
Only the insulin part is remembered.
Do this: Name both the duct and the islets.
Usually costs: 1 mark.
Exam tips
- Use the four-column table: gland, location, secretion, function.
- Hormone: chemical messenger, into blood, target organ.
- Link each disorder to a hormone.
- Pancreas is both exocrine and endocrine.
Practice questions on Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands
Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.
Q1 · 1 mark · Very short answerBoard level
Name the gland that lies on top of each kidney and the hormone it secretes.
Hint
Emergency hormone.
Answer
The adrenal gland; adrenaline.
Q2 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Hormones reach their target organs through the blood.
Reason (R): Endocrine glands have no ducts.
(a) (A) is true and (R) is false.
(b) (A) is false and (R) is true.
(c) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(d) Both (A) and (R) are true, but (R) is not the correct explanation of (A).Hint
Where does a ductless gland pour?
Answer
(c).
Q3 · 3 marks · Short answerHarder board level
Compare nervous control and hormonal control in three points. Say which one you would expect to act in pulling your hand away from a hot pan and which in the growth spurt of a teenager.
Hint
Speed, carrier, duration.
Answer
Nervous control uses electrical impulses along nerves, is very fast and short-lived; hormonal control uses chemicals carried in blood, is slower and longer-lasting. Pulling the hand away is nervous control; the growth spurt is hormonal.
Q4 · 3 marks · Long answerHarder board level
A person feels tired and gains weight and the neck is swollen. Name the gland involved and the likely deficiency, and explain how the swelling arises.
Hint
Iodine.
Answer
The thyroid gland, with a lack of iodine in the diet. Thyroxine contains iodine; without it the gland cannot make enough hormone and enlarges, causing goitre. Iodised salt prevents it.
Q5 · 3 marks · Case-basedHOTS / competency
Read and answer.
Suppose a doctor finds that a patient's blood sugar stays high and sugar appears in the urine.
(a) Name the disorder. (1)
(b) Name the hormone and the gland concerned. (1)
(c) State one way to manage it. (1)Hint
Insulin.
Answer
(a) Diabetes mellitus. (b) Insulin, from the pancreas (too little). (c) Diet and exercise, or insulin injections if needed.
Test your recall
Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.
1.Which gland secretes thyroxine?Show answer
The thyroid.
2.Which hormone is the emergency hormone?Show answer
Adrenaline.
3.What disorder arises from too little insulin?Show answer
Diabetes mellitus.
4.Which element does thyroxine contain?Show answer
Iodine.
5.Which gland is the master gland?Show answer
The pituitary.
Exocrine and Endocrine Glands, Hormones and the Four Hormonal Glands: frequently asked questions
Are other glands such as testes and ovaries asked here?
The syllabus names thyroid, adrenal, pancreas and pituitary only, in tabular form.
Is glucagon compulsory?
Insulin is the key one; glucagon is useful for a complete answer.
Where is adolescence covered?
In the next topic.
Do I need disorders?
Know goitre, diabetes and gigantism as common application questions.