BiologyICSE Class 10 · Endocrine System

The Pituitary Gland, Its Hormones and Feedback Control (ICSE Class 10 Biology)

Updated 16 October 2026 · Fact-checked

The pituitary is a pea-sized gland at the base of the brain, attached to the hypothalamus. It secretes growth hormone, tropic hormones such as TSH and ACTH that control other glands, ADH that increases water reabsorption, and oxytocin that contracts the uterus. Thyroxine levels are kept steady by negative feedback on TSH.

Notice the dashed red loop: when thyroxine rises, it tells the pituitary to release less TSH, keeping the level steady.

Illustration drawn for QuestionBuddy.

Understand Pituitary Gland and Feedback Control

Hormones and endocrine glands. A hormone is a chemical secreted by an endocrine (ductless) gland directly into the blood, which carries it to a target organ where it acts. Endocrine glands are ductless; exocrine glands (salivary, sweat) pour secretions through ducts. Hormones work slowly but their effects last longer than nerve impulses.

Location and shape. The pituitary is a small, pea-sized gland at the base of the brain, attached by a stalk to the hypothalamus, which controls it.

Why 'master gland'? Its tropic hormones control the activity of several other endocrine glands.

Hormones of the pituitary.

Hormone	Target	Action
Growth hormone (GH)	bones, muscles	growth of the body
TSH (thyroid-stimulating hormone)	thyroid	stimulates thyroxine secretion
ACTH (adrenocorticotropic hormone)	adrenal cortex	stimulates cortical hormones
FSH and LH (gonadotropins)	testes, ovaries	development of gametes and sex hormones
ADH (antidiuretic hormone, vasopressin)	kidney tubules	increases reabsorption of water, so less urine
Oxytocin	uterus, mammary glands	contraction of the uterus during childbirth; release of milk

Too little or too much.

Hormone	Hyposecretion	Hypersecretion
GH in childhood	dwarfism: short but proportionate, normal intelligence	gigantism: abnormally tall
GH in adults	—	acromegaly: enlarged hands, feet, jaw and face
ADH	diabetes insipidus: large volumes of dilute urine, great thirst	less urine, water retained

Diabetes insipidus versus diabetes mellitus. Insipidus: pituitary, lack of ADH, much dilute urine without sugar. Mellitus: pancreas, lack of insulin, high blood sugar and sugar in urine.

Feedback control with reference to TSH (brief). Hormone levels must not swing too high or too low.
1. Thyroxine in the blood falls → the pituitary secretes more TSH.
2. TSH stimulates the thyroid → more thyroxine.
3. Thyroxine rises above normal → it inhibits TSH secretion.
4. Less TSH → less thyroxine → level returns to normal.
This is negative feedback: the result switches off its own cause, like a thermostat switching off a heater.

Flow chart: feedback. Low thyroxine → pituitary ↑ TSH → thyroid ↑ thyroxine → high thyroxine → pituitary ↓ TSH → thyroid ↓ thyroxine → normal.

Draw-and-label checklist: feedback loop. Box 'Pituitary' at the top; box 'Thyroid' below; arrow down labelled TSH (+); arrow up labelled thyroxine with a minus sign (−, inhibits) to the pituitary; box 'body cells: metabolism' to the side receiving thyroxine.

Draw-and-label checklist: gland positions. On a body outline: pituitary at the base of the brain, thyroid in the neck on the trachea, adrenals on top of the kidneys, pancreas behind the stomach in the loop of the duodenum.

Pituitary Gland and Feedback Control: key facts

Pituitary hormones: GH body growth
TSH thyroid
ACTH adrenal cortex
FSH, LH gonads
ADH water reabsorption
Oxytocin uterus contraction, milk release; Tropic hormones control other glands.
Disorders: GH low in child dwarfism
GH high in child gigantism
GH high in adult acromegaly
ADH low diabetes insipidus; Always give gland, hormone, hypo or hyper.
Negative feedback: Low thyroxine
More TSH
More thyroxine
High thyroxine inhibits TSH
Level back to normal; The product switches off its own production.

GH	body growth
TSH	thyroid
ACTH	adrenal cortex
FSH, LH	gonads
ADH	water reabsorption
Oxytocin	uterus contraction, milk release

GH low in child	dwarfism
GH high in child	gigantism
GH high in adult	acromegaly
ADH low	diabetes insipidus

How to answer Pituitary Gland and Feedback Control questions

ICSE asks you to define a hormone, name the pituitary hormone for a function, link a disorder to hypo- or hypersecretion, distinguish the two diabetes, and outline TSH feedback.

1Define a hormone with three points: endocrine gland, directly into blood, target organ.
2Match function to hormone: urine volume → ADH; childbirth → oxytocin; height → GH.
3For disorders, write gland + hormone + hypo or hyper.
4When a gland is asked, answer with the gland, not the hormone.
5For feedback, write the four-step loop with 'inhibits'.

Pituitary Gland and Feedback Control 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.

Thirsty all the time

Suppose after a head injury a man passes about 10 litres of pale urine a day and is always thirsty, but his urine has no sugar.

Which hormone is lacking, and why does it cause these symptoms?

Try it first, then show the solutionSolution

Very large volumes of dilute urine without sugar point to diabetes insipidus.
It is caused by lack of ADH from the pituitary.
Without ADH, the kidney tubules reabsorb little water, so most of the filtrate's water leaves as urine.
Water loss makes him very thirsty.

Answer: ADH (vasopressin) deficiency; tubules cannot reabsorb water, so much dilute urine and thirst.

Memory hook: Anti-Diuretic = Against Draining.

Room thermostat

Suppose an air conditioner switches off when the room reaches 24 °C and on again when it warms up.

Compare this with control of thyroxine.

Try it first, then show the solutionSolution

The thermostat senses temperature; the pituitary senses thyroxine level.
When the room is warm, the AC runs; when thyroxine is low, TSH is released.
When the target is reached, the AC stops; high thyroxine inhibits TSH.
Both keep the level within a narrow range: negative feedback.

Answer: Like a thermostat, high thyroxine switches off TSH and low thyroxine switches it on.

Memory hook: Feedback = thermostat in the body.

Tricks to remember Pituitary Gland and Feedback Control

Short memory aids. Say each one aloud once, then use it on a question the same day.

GOAT for the main pituitary hormones
Growth hormone, Oxytocin, ADH, Tropic hormones.
Use it when: Listing the syllabus hormones.
Oxytocin = Out-come
Oxytocin helps the baby come out and the milk come out.
Use it when: Function of oxytocin.
Child small or tall, adult jaw
GH low in child: dwarf; high in child: giant; high in adult: acromegaly (big jaw, hands).
Use it when: GH disorders.

Pituitary Gland and Feedback Control: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Saving water · 1 mark · MCQBoard level

When the body is short of water, the pituitary releases:
(a) ADH, which increases water reabsorption in the kidney tubules (b) ADH, which decreases water reabsorption (c) oxytocin, which increases water reabsorption (d) adrenaline, which increases urine output

Try it first, then show the solutionSolution

ADH (vasopressin) makes the tubules reabsorb more water, so less, more concentrated urine is passed.

Answer: (a) ADH, which increases water reabsorption in the kidney tubules.

Example 2: Is saliva a hormone? · 1 mark · Very short answerBoard level

A student says, 'Saliva is a hormone because it is a chemical made by a gland.' Using the full definition of a hormone, explain why she is wrong. (Defining a hormone was asked in 2024.)

Try it first, then show the solutionSolution

A hormone is secreted by an endocrine (ductless) gland directly into the blood and carried to a target organ; saliva is poured by exocrine salivary glands through ducts into the mouth and acts there.

Answer: Saliva comes from exocrine glands through ducts and acts locally; a hormone is secreted by an endocrine gland directly into the blood and acts on a distant target organ.

Example 3: Master gland · 3 marks · Short answerHarder board level

Why is the pituitary called the master gland? Name two tropic hormones and their target glands.

Try it first, then show the solutionSolution

Its tropic hormones control the secretion of other endocrine glands (1 mark).
TSH: thyroid (1 mark).
ACTH: adrenal cortex (or FSH and LH: gonads) (1 mark).

Answer: It controls other glands via tropic hormones such as TSH (thyroid) and ACTH (adrenal cortex).

Example 4: ADH and oxytocin compared · 3 marks · Short answerHarder board level

Compare ADH and oxytocin, both released from the pituitary, by (a) target organ, (b) action, and (c) one situation in which each is released.

Try it first, then show the solutionSolution

(a) ADH: kidney tubules (distal tubule and collecting duct); oxytocin: uterus and mammary glands (1 mark).
(b) ADH increases water reabsorption, so less urine forms; oxytocin causes contraction of the uterus and release of milk (1 mark).
(c) ADH: when the body is dehydrated, e.g. after heavy sweating; oxytocin: during childbirth or breastfeeding (1 mark).

Answer: ADH: kidney tubules, more water reabsorbed, released when dehydrated. Oxytocin: uterus and mammary glands, contractions and milk release, released at childbirth and feeding.

Example 5: Too many thyroxine tablets · 3 marks · Case-basedHOTS / competency

Suppose a patient takes more thyroxine tablets than prescribed for several weeks. (a) Predict the change in her TSH level. (b) Explain using feedback. (c) What happens to the output of her own thyroid gland, and why?

Try it first, then show the solutionSolution

(a) TSH falls (1 mark).
(b) High thyroxine in the blood inhibits the pituitary, so less TSH is released (negative feedback) (1 mark).
(c) Her thyroid secretes less thyroxine, because it receives little TSH to stimulate it (1 mark).

Answer: (a) Falls. (b) High thyroxine inhibits TSH secretion. (c) Her own thyroid output falls for lack of TSH stimulation.

Example 6: Short but healthy · 3 marks · Case-basedHOTS / competency

Suppose a 12-year-old is 120 cm tall when the average for his age is 150 cm. His body is well-proportioned and his school work is excellent. (a) What percentage of the average height has he reached? (b) Name a likely hormonal cause. (c) Why is a thyroid cause less likely?

Try it first, then show the solutionSolution

(a) 120 ÷ 150 × 100 = 80% (1 mark).
(b) Hyposecretion of growth hormone from the pituitary (pituitary dwarfism) (1 mark).
(c) Thyroxine deficiency (cretinism) also causes mental retardation, but his intelligence is normal (1 mark).

Answer: (a) 80%. (b) Low GH. (c) Normal intelligence rules out cretinism.

Where students lose marks in Pituitary Gland and Feedback Control

The slips examiners see most often, and what to write instead.

Mistake: Adrenaline for vasopressin
CISCE examiners' comments (2024): for the hormone that affects urination, candidates confused adrenaline and vasopressin.
Do this: Vasopressin (ADH) controls urine volume.
Usually costs: 1 mark.
Mistake: Hormone named when the gland is asked
CISCE examiners' comments (2024): distinguishing diabetes mellitus and insipidus by gland, candidates wrote hormone names instead of glands.
Do this: Mellitus: pancreas. Insipidus: pituitary.
Usually costs: 1-2 marks.
Mistake: Hormone definition missing blood or gland
CISCE examiners' comments (2024): candidates did not mention secretion by endocrine glands or transport by blood.
Do this: Gland + blood + target organ.
Usually costs: 1 mark.
Mistake: Progesterone for uterine contraction
CISCE examiners' comments (2025): candidates confused oxytocin with oestrogen or progesterone.
Do this: Oxytocin from the pituitary contracts the uterus.
Usually costs: 1 mark.

Exam tips

Master gland: tropic hormones.
ADH: water reabsorption; lack → diabetes insipidus.
Oxytocin: childbirth and milk release.
Feedback: high thyroxine inhibits TSH.

Practice questions on Pituitary Gland and Feedback Control

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 · MCQBoard level
Which pair is correctly matched?
(a) TSH: adrenal cortex (b) ADH: uterus (c) ACTH: adrenal cortex (d) oxytocin: kidney tubules
Hint
Adreno-cortico-tropic.
Answer
(c) ACTH: adrenal cortex.
Q2 · 1 mark · Very short answerBoard level
Name the part of the brain to which the pituitary is attached.
Hint
Below the thalamus.
Answer
Hypothalamus.
Q3 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Excess growth hormone in an adult causes gigantism.
Reason (R): Long bones of adults have stopped growing in length.
(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
Adults get acromegaly.
Answer
(b).
Q4 · 2 marks · Short answerHarder board level
Classify each as endocrine or exocrine, giving a reason: (a) sweat glands; (b) thyroid; (c) the acini of the pancreas.
Hint
Duct or no duct?
Answer
(a) Exocrine: sweat passes through ducts to the skin. (b) Endocrine: ductless, thyroxine goes directly into blood. (c) Exocrine: pancreatic juice passes through the pancreatic duct to the duodenum.
Q5 · 2 marks · Short answerHarder board level
Why may a doctor give an injection of oxytocin to a mother whose labour is very slow?
Hint
Childbirth hormone.
Answer
Oxytocin causes strong contractions of the uterus, which help push the baby out.
Q6 · 2 marks · Short answerHarder board level
What is acromegaly? State its cause.
Hint
Adult excess.
Answer
A disorder in which the hands, feet, jaw and face enlarge; caused by hypersecretion of growth hormone in adults.
Q7 · 2 marks · Short answerHarder board level
In a feedback diagram, an arrow from the thyroid back to the pituitary is marked with a minus sign. What does this arrow represent, and what would happen to the thyroxine level if this inhibition were lost?
Hint
The brake on TSH.
Answer
It shows thyroxine inhibiting TSH secretion (negative feedback). Without it the pituitary would keep releasing TSH, so the thyroid would keep secreting and thyroxine would rise above normal.
Q8 · 3 marks · Case-basedHOTS / competency
Read and answer.
Suppose a patient's urine output falls from 10 L to 1.5 L a day after treatment with a nasal spray.
(a) By how many litres did output fall? (1)
(b) Which hormone does the spray probably supply? (1)
(c) On which part of the kidney does it act? (1)
Hint
Diabetes insipidus treatment.
Answer
(a) 10 − 1.5 = 8.5 L. (b) ADH (vasopressin). (c) The kidney tubules (distal tubule and collecting duct), increasing water reabsorption.

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.Where is the pituitary located?Show answer
At the base of the brain, attached to the hypothalamus.
2.What is another name for ADH?Show answer
Vasopressin.
3.What does TSH stimulate?Show answer
The thyroid gland.
4.What disorder results from excess GH in childhood?Show answer
Gigantism.
5.What kind of feedback controls thyroxine?Show answer
Negative feedback.

Pituitary Gland and Feedback Control: frequently asked questions

Do I need anterior and posterior lobes?

Not for 2027. Know the hormones listed: growth hormone, tropic hormones, ADH and oxytocin.

Is the hypothalamus an endocrine gland?

It controls the pituitary, but ICSE Class 10 only requires the four glands: pituitary, thyroid, adrenal and pancreas.

Is feedback only for TSH?

Many hormones are controlled by feedback, but the syllabus asks for a brief idea with reference to TSH.

Are dwarfs due to GH deficiency mentally affected?

No. Pituitary dwarfs are proportionate with normal intelligence, unlike cretins.