BiologyISC Class 11 · Chemical Coordination and Integration

Thyroid, Parathyroid, Adrenal, Pancreatic and Gonadal Hormones with Their Disorders

Updated 17 October 2026 · Fact-checked

The thyroid makes thyroxine and calcitonin; the parathyroid makes PTH, which raises blood Ca²⁺; the adrenal cortex makes cortisol and aldosterone and the medulla makes adrenaline; the pancreatic islets make insulin (lowers blood glucose) and glucagon (raises it); the gonads make testosterone, oestrogen and progesterone. Their under- and over-secretion causes characteristic disorders.

Outline of a human body with labelled endocrine glands: pineal, pituitary, thyroid, parathyroid, thymus, pancreatic islets, adrenal and gona — Note where the thyroid, parathyroids, pancreatic islets, adrenals and gonads sit in the body, since these are the glands this topic covers.
Picture: Internet Archive Book Images · Public domain · Wikimedia Commons

Notice each level has two opposing hormones: the green up triangle raises it, the red down triangle lowers it.

Illustration drawn for QuestionBuddy.

Understand Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal Hormones

Thyroid. Two lobes joined by an isthmus on the trachea. Thyroxine (T₄) and triiodothyronine (T₃) need iodine and regulate basal metabolic rate, supporting the development of the nervous system and RBC formation. *Hypothyroidism:* iodine deficiency causes simple (endemic) goitre (enlarged gland); in infants cretinism (stunted growth, mental retardation); in adults myxoedema (low BMR). *Hyperthyroidism:* exophthalmic goitre (Graves' disease) with protruding eyes, high BMR. Calcitonin lowers blood calcium.

Parathyroid. Four small glands on the back of the thyroid; parathyroid hormone (PTH) increases blood Ca²⁺ (by releasing it from bone and by reabsorption and absorption), acting oppositely to calcitonin. Thymus: thymosin promotes differentiation of T-lymphocytes (cell-mediated immunity); it degenerates with age.

Adrenal. *Cortex:* glucocorticoids (cortisol: gluconeogenesis, anti-inflammatory, maintains cardiac function), mineralocorticoids (aldosterone: Na⁺ and water reabsorption) and small amounts of sex steroids. *Medulla:* adrenaline and noradrenaline (emergency hormones): increase heart rate, alertness, blood glucose and pupil dilation ("fight or flight"). *Disorders:* Addison's disease (deficiency of the cortex hormones: weakness, low BP); Cushing's syndrome (excess cortisol).

Pancreas. Islets of Langerhans: α cells secrete glucagon (raises blood glucose by glycogenolysis and gluconeogenesis); β cells secrete insulin (lowers blood glucose by promoting uptake into cells and glycogenesis). *Diabetes mellitus:* insulin deficiency or resistance, high blood glucose, glycosuria, excessive urination and thirst, ketone bodies; treated with insulin therapy.

Gonads. *Testis:* testosterone (Leydig cells) for male sex organs, secondary sexual characters and spermatogenesis. *Ovary:* oestrogen (growth of follicles, secondary sexual characters) and progesterone (maintains pregnancy). Others: the heart secretes ANF, the kidney erythropoietin (RBC formation), and the gastrointestinal tract gastrin, secretin, CCK and GIP.

Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal Hormones: key facts

Thyroid: T₄ and T₃ (need iodine) | Calcitonin; Goitre, cretinism, myxoedema, Graves' disease.
Calcium control: Calcitonin lowers Ca²⁺ | PTH raises Ca²⁺; Opposite actions.
Blood glucose: $I n s u l in (β ce l l s) l o w er s ∣ Gl u c a g o n (α ce l l s) r ai ses$; Diabetes mellitus: insulin deficiency.
Adrenal: $C or t e x : cor t i so l, a l d os t er o n e ∣ M e d u l l a : a d r e na l in e, n or a d r e na l in e$; Addison's: cortex hyposecretion.

Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal 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.

A farmer in an iodine-poor hill region

Suppose people in a hill village have swollen necks and fatigue, and the local salt is not iodised.

Explain the cause and the remedy.

Try it first, then show the solutionSolution

Iodine is needed to make thyroxine; its deficiency lowers the hormone level.
Low thyroxine removes the negative feedback, TSH rises and stimulates the gland, which enlarges: goitre.
The remedy is iodised salt in the diet.

Answer: Iodine deficiency goitre; use iodised salt.

Memory hook: Low hormone, high TSH, big gland.

Tricks to remember Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal Hormones

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

Insulin lowers, glucagon gains
Opposing hormones of the pancreas.
Use it when: Blood glucose control.
Cortex: salt, sugar, sex; medulla: emergency
Mineralocorticoids, glucocorticoids and sex steroids; adrenaline.
Use it when: Adrenal hormones.

Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal Hormones: solved examples

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

Example 1: Hormone for emergencies · 1 mark · MCQBoard level

The hormone released in emergencies from the adrenal medulla is:
(a) cortisol
(b) aldosterone
(c) adrenaline
(d) insulin

Try it first, then show the solutionSolution

Adrenaline prepares the body for fight or flight.

Answer: (c) adrenaline

Example 2: Thyroid disorders · 3 marks · Short answerBoard level

Explain the causes and effects of simple goitre, cretinism and exophthalmic goitre.

Try it first, then show the solutionSolution

Simple goitre: iodine deficiency, enlarged thyroid. (1 mark)
Cretinism: severe thyroxine deficiency in infants, stunted growth and mental retardation. (1 mark)
Exophthalmic goitre: hyperthyroidism, enlarged gland, protruding eyes and high BMR. (1 mark)

Answer: Iodine deficiency; infant hypothyroidism; hyperthyroidism.

Example 3: Blood glucose regulation · 4 marks · Short answerHarder board level

Describe how insulin and glucagon regulate blood glucose after a meal and during fasting. Name the cells that secrete them.

Try it first, then show the solutionSolution

After a meal blood glucose rises; β cells of the islets of Langerhans secrete insulin. (1 mark)
Insulin promotes glucose uptake by cells and conversion to glycogen (glycogenesis), lowering blood glucose. (1 mark)
During fasting glucose falls; α cells secrete glucagon, stimulating glycogen breakdown and gluconeogenesis in the liver. (1.5 marks)
The two hormones act antagonistically to keep glucose in the normal range. (0.5 mark)

Answer: Insulin from β cells lowers; glucagon from α cells raises.

Example 4: Calcium homeostasis · 4 marks · Short answerHarder board level

Name the hormones controlling blood calcium and their effects. Explain why a person who has had the parathyroid glands removed may show tetany.

Try it first, then show the solutionSolution

PTH raises blood Ca²⁺ by releasing it from bone and increasing absorption in the kidney and gut. (1.5 marks)
Calcitonin lowers blood Ca²⁺ by promoting deposition in bone. (1 mark)
Without PTH the blood calcium falls, increasing the excitability of nerves and muscles. (0.75 mark)
This causes rapid spasms of muscle, called tetany. (0.75 mark)

Answer: PTH raises, calcitonin lowers; low Ca²⁺ causes tetany.

Example 5: Diabetes and the adrenal gland · 5 marks · Long answerHOTS / competency

A patient has high blood glucose, glucose in urine and passes large volumes of urine. (i) Name the disease and the hormone concerned. (ii) Explain the polyuria. (iii) Distinguish the disease from Addison's disease. (iv) State why adrenaline raises blood glucose.

Try it first, then show the solutionSolution

(i) Diabetes mellitus; deficiency (or resistance) of insulin. (1 mark)
(ii) The glucose in the filtrate exceeds the reabsorption capacity of the PCT and holds water in the urine by osmosis. (1.5 marks)
(iii) Addison's disease is a deficiency of adrenal cortex hormones (cortisol and aldosterone), giving weakness and low blood pressure. (1.5 marks)
(iv) Adrenaline stimulates glycogen breakdown in the liver, giving energy for fight or flight. (1 mark)

Answer: Diabetes mellitus (insulin); osmotic polyuria; Addison's is a cortex deficiency; adrenaline mobilises glucose.

Where students lose marks in Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal Hormones

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

Mistake: Reversing insulin and glucagon
Saying glucagon lowers blood glucose.
Do this: Insulin lowers, glucagon raises.
Usually costs: 2 marks.
Mistake: Confusing Addison's and Cushing's
Giving hyposecretion for Cushing's.
Do this: Addison's: deficiency; Cushing's: excess cortisol.
Usually costs: 1 mark.
Mistake: Wrong gland for calcitonin
Parathyroid.
Do this: Calcitonin comes from the thyroid; PTH from the parathyroid.
Usually costs: 1 mark.

Exam tips

Make a table of gland, hormone, function and disorder.
Explain feedback in at least one example.
Write the reason for each symptom of a disorder.
Show the antagonistic pairs clearly.

Practice questions on Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal 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 deficiency of iodine in food leads to:
(a) diabetes
(b) goitre
(c) Addison's disease
(d) gigantism
Hint
Thyroid hormones need iodine.
Answer
(b) goitre
Q2 · 2 marks · Short answerBoard level
Name the hormone that lowers blood calcium level and the gland that secretes it.
Hint
Opposite to PTH.
Answer
Calcitonin, secreted by the thyroid gland.
Q3 · 3 marks · Short answerHarder board level
What is the role of thymosin?
Hint
Think about the immune system.
Answer
Thymosin, from the thymus, promotes the differentiation of T-lymphocytes that provide cell-mediated immunity; its secretion declines with age.
Q4 · 3 marks · Short answerHarder board level
Differentiate between glucocorticoids and mineralocorticoids.
Hint
Cortisol and aldosterone.
Answer
Glucocorticoids (cortisol) regulate carbohydrate metabolism, are anti-inflammatory and stimulate gluconeogenesis. Mineralocorticoids (aldosterone) regulate Na⁺ and water reabsorption in the kidney.
Q5 · 3 marks · Assertion-reasonHarder board level
Assertion (A): Insulin and glucagon are antagonistic hormones. Reason (R): Insulin lowers and glucagon raises blood glucose. Choose: (a) both true and R explains A (b) both true, R does not explain A (c) A true, R false (d) A false, R true.
Hint
Opposite effects.
Answer
(a) Both true and R explains A.
Q6 · 4 marks · Case-basedHOTS / competency
Case study: Suppose a patient has a swollen neck, low body temperature and slow metabolism.
(i) Name the gland. (1 mark)
(ii) Name the hormone involved. (1 mark)
(iii) Name the disorder in adults caused by its deficiency. (1 mark)
(iv) State a dietary remedy. (1 mark)
Hint
Think of hypothyroidism.
Answer
(i) The thyroid. (ii) Thyroxine (T₄). (iii) Myxoedema (hypothyroidism). (iv) Iodised salt (iodine-rich food).

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.Cells secreting insulin?Show answer
β cells.
2.Hormone of the thymus?Show answer
Thymosin.
3.Emergency hormone?Show answer
Adrenaline.
4.Hormone raising Ca²⁺?Show answer
PTH.

Thyroid, Parathyroid, Adrenal, Pancreas and Gonadal Hormones: frequently asked questions

Why is the adrenal medulla hormone called an emergency hormone?

Adrenaline and noradrenaline increase alertness, heart rate and blood glucose to prepare the body for stress.

What does the kidney secrete as a hormone?

Erythropoietin, which stimulates the formation of red blood cells.

What is the function of progesterone?

It supports pregnancy and prepares the uterus for implantation.