BiologyCBSE Class 11 · Chemical Coordination and Integration

Hypothalamus, Pituitary, Pineal, Thyroid and Parathyroid Hormones

Updated 17 October 2026 · Fact-checked

The hypothalamus controls the pituitary through releasing and inhibiting hormones. The adenohypophysis secretes GH, PRL, TSH, ACTH, LH and FSH; the neurohypophysis stores and releases oxytocin and vasopressin. The thyroid secretes T3, T4 and TCT, the parathyroids secrete PTH, which raises blood calcium, and the pineal secretes melatonin.

Understand Pituitary, Thyroid and Parathyroid Hormones

Endocrine glands and hormones. Hormones are non-nutrient chemicals produced in trace amounts that act as intercellular messengers. The endocrine glands lack ducts and secrete into blood.

Hypothalamus. Hormones are releasing hormones (stimulate pituitary hormone secretion, e.g. GnRH, which stimulates LH and FSH) and inhibiting hormones (e.g. somatostatin inhibits growth hormone release). Hypothalamic hormones reach the anterior pituitary through the portal circulation; the posterior pituitary is under neural regulation.

Pituitary.

Adenohypophysis (anterior): growth hormone (GH): overproduction in childhood causes gigantism, in adults acromegaly, underproduction causes pituitary dwarfism; prolactin (PRL): milk formation; TSH: stimulates thyroid; ACTH: stimulates adrenal cortex; LH and FSH: gonadotrophins (in males LH stimulates androgens, FSH spermatogenesis; in females LH ovulation and corpus luteum, FSH follicular growth); MSH acts on melanocytes (pars intermedia, in some animals).
Neurohypophysis (posterior): stores and releases oxytocin (contraction of uterus during childbirth, milk ejection) and vasopressin (ADH) (water reabsorption in kidney; deficiency causes diabetes insipidus, with dilute urine and dehydration), both made in the hypothalamus.

Pineal gland. Secretes melatonin: regulates the diurnal (24-hour) rhythm (sleep-wake cycle, body temperature), metabolism, pigmentation and the menstrual cycle, and influences defence.

Thyroid. Two lobes on either side of the trachea, joined by an isthmus. Follicles secrete tetraiodothyronine (T₄, thyroxine) and triiodothyronine (T₃); iodine is needed. They regulate the basal metabolic rate, support RBC formation, and affect carbohydrate, protein and fat metabolism, and development of the CNS. Thyrocalcitonin (TCT) from parafollicular cells lowers blood Ca²⁺ (by suppressing bone resorption).

Hypothyroidism from iodine deficiency: simple goitre (enlarged thyroid); in pregnancy, cretinism (stunted growth, mental retardation, low IQ); in adults, myxoedema (low BMR, oedema). Hyperthyroidism (cancer, nodules): increased BMR and weight loss; exophthalmic goitre (Graves' disease) with protruding eyeballs.

Parathyroid. Four tiny glands on the back of the thyroid. Secrete parathyroid hormone (PTH), which increases blood Ca²⁺ by stimulating bone resorption, reabsorption of Ca²⁺ by renal tubules and Ca²⁺ absorption from digested food; it works in opposition to TCT.

Table: hormone, source, target, effect.

Draw and label: the endocrine glands of the human body or the hypothalamus-pituitary link.

Pituitary, Thyroid and Parathyroid Hormones: key facts

Pituitary anterior: $G H ∣ P R L ∣ T S H ∣ A C T H ∣ L H ∣ F S H$; Adenohypophysis
Pituitary posterior: $O x y t oc in ∣ v a so p r ess in (A D H)$; Stored; made in hypothalamus
Thyroid: T3, T4 (raise BMR) | TCT (lowers Ca2+); Iodine needed
Calcium control: PTH raises Ca2+ | TCT lowers Ca2+; Opposing

How to answer Pituitary, Thyroid and Parathyroid Hormones questions

Questions give a symptom and ask for the hormone and gland, or ask for roles.

1Identify the gland from the symptom: giant child GH; goitre iodine; tetany low Ca.
2Name the hormone and the target.
3State excess and deficiency effects.
4For antagonists, pair PTH with TCT.
5Mention the hypothalamic control.

Pituitary, Thyroid and Parathyroid Hormones 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.

Hill village goitre

Suppose people in a hill village develop swellings in the neck and some babies have stunted growth.

Identify the cause and the names of the conditions.

Try it first, then show the solutionSolution

Iodine deficiency reduces thyroid hormone, causing the thyroid to enlarge as simple goitre.
In babies of deficient mothers this causes cretinism.
Iodised salt provides iodine and prevents these.

Answer: Iodine deficiency: goitre and cretinism.

Memory hook: Iodine feeds the thyroid.

Tricks to remember Pituitary, Thyroid and Parathyroid Hormones

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

FLAT PiG
FSH, LH, ACTH, TSH, Prolactin, GH: the six anterior pituitary hormones.
Use it when: Anterior pituitary
PTH up, TCT down
Parathyroid hormone raises calcium; calcitonin lowers it.
Use it when: Calcium
Oxytocin = out
Oxytocin pushes out the baby and milk.
Use it when: Oxytocin

Pituitary, Thyroid and Parathyroid Hormones: solved examples

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

Example 1: Pituitary regions · 3 marks · Short answerBoard level

Name the two lobes of the pituitary and the hormones released by each (list at least four).

Try it first, then show the solutionSolution

Adenohypophysis: GH, PRL, TSH, ACTH, LH, FSH (1 mark).
Neurohypophysis: oxytocin and vasopressin (1 mark).
Posterior pituitary hormones are made in the hypothalamus (neurosecretory cells), transported along axons, and stored in and released from the neurohypophysis (1 mark).

Answer: Anterior six; posterior two.

Example 2: Calcium balance · 3 marks · Short answerBoard level

Explain how PTH and TCT control blood calcium.

Try it first, then show the solutionSolution

PTH raises blood Ca2+ by bone resorption, renal reabsorption and gut absorption (1 mark).
TCT lowers Ca2+ by reducing bone resorption (1 mark).
They act in opposition, keeping calcium within limits (1 mark).

Answer: PTH up, TCT down.

Example 3: Thyroid disorders · 4 marks · Short answerHarder board level

Distinguish simple goitre, cretinism and exophthalmic goitre with cause.

Try it first, then show the solutionSolution

Simple goitre: iodine deficiency, enlarged thyroid (1 mark).
Cretinism: low thyroid hormone in a mother or child, mental retardation (1 mark).
Exophthalmic goitre: hyperthyroidism, protruding eyeballs (1 mark).
Hypo gives low BMR; hyper gives high BMR (1 mark).

Answer: Hypo versus hyper.

Example 4: Growth hormone · 3 marks · Short answerHarder board level

Compare the effects of GH excess before and after puberty, and of GH deficiency.

Try it first, then show the solutionSolution

Excess in childhood: gigantism (1 mark).
Excess in adults: acromegaly (1 mark).
Deficiency in childhood: pituitary dwarfism (1 mark).

Answer: Gigantism, acromegaly, dwarfism.

Example 5: Diabetes insipidus · 5 marks · Long answerHOTS / competency

A patient passes large volumes of dilute urine and is always thirsty, with normal blood sugar. Identify the hormone and gland, explain the symptoms, and say how it differs from diabetes mellitus.

Try it first, then show the solutionSolution

Deficient ADH (vasopressin) from the neurohypophysis (1 mark).
Less water reabsorbed in the collecting duct, so more dilute urine (1 mark).
Loss of water causes thirst (1 mark).
Blood sugar is normal, unlike diabetes mellitus (insulin related) (1 mark).
Urine has no glucose in diabetes insipidus (1 mark).

Answer: ADH deficiency; glucose normal.

Where students lose marks in Pituitary, Thyroid and Parathyroid Hormones

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

Mistake: ADH from the anterior pituitary
Gland mixed.
Wrong working
ADH comes from adenohypophysis.
Right working
From the neurohypophysis.
Do this: Posterior.
Usually costs: 1 mark.
Mistake: TCT raises calcium
Role reversed.
Wrong working
TCT raises Ca2+.
Right working
TCT lowers; PTH raises.
Do this: PTH up.
Usually costs: 1 mark.
Mistake: Thyroxine without iodine
Component forgotten.
Wrong working
Thyroxine contains no iodine.
Right working
Thyroid hormones need iodine.
Do this: Iodine.
Usually costs: 1 mark.

Exam tips

Use tables for glands and hormones.
Remember the six anterior hormones.
Write both excess and deficiency effects.
State antagonists clearly.

Practice questions on Pituitary, Thyroid and Parathyroid Hormones

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
The hormone that lowers blood calcium is
(a) PTH (b) TCT (c) ADH (d) oxytocin
Hint
Thyroid.
Answer
(b).
Q2 · 1 mark · Assertion-reasonHarder board level
Assertion (A): The posterior pituitary does not make its own hormones.
Reason (R): Oxytocin and vasopressin are made in the hypothalamus.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Stored there.
Answer
(a).
Q3 · 2 marks · Very short answerBoard level
Name the hormone of the pineal gland and two functions.
Hint
Melatonin.
Answer
Melatonin; regulates the 24-hour (diurnal) rhythm, sleep-wake cycle and body temperature, also affects metabolism and pigmentation.
Q4 · 4 marks · Case-basedHarder board level
Read and answer.
Suppose a child has stunted growth and a low IQ, with a mother who lacked iodine.
(a) Name the condition. (1)
(b) Name the hormones lacking. (1)
(c) Give a preventive measure. (2)
Hint
Cretinism.
Answer
(a) Cretinism. (b) Thyroxine (T4) and T3. (c) Iodised salt in the diet of the mother and child.
Q5 · 3 marks · Short answerHOTS / competency
Suppose the parathyroids are accidentally removed in surgery. Predict the effect on blood calcium and muscles, and name the condition.
Hint
Low Ca2+.
Answer
PTH would fall, so blood Ca2+ falls and nerves and muscles become overexcitable, leading to tetany (muscle spasms).

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.Master gland?Show answer
Pituitary.
2.Hormone for uterine contraction?Show answer
Oxytocin.
3.Disorder of iodine deficiency?Show answer
Simple goitre.
4.Hormone raising calcium?Show answer
PTH.
5.Melatonin source?Show answer
Pineal gland.
6.Dwarfism cause?Show answer
Low GH in childhood.

Pituitary, Thyroid and Parathyroid Hormones: frequently asked questions

What is a hormone?

A chemical messenger in trace amounts.

What controls the pituitary?

The hypothalamus.

What does T4 do?

Regulates metabolic rate.

Where are parathyroids?

On the back of the thyroid.

What is cretinism?

Stunted growth and mental retardation from low thyroid hormone.