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Score — click each question to reveal the answer
Q1
Steroid and thyroid hormones act mainly by:
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A. binding intracellular receptors and altering gene transcription
B. opening membrane ion channels
C. generating cAMP
D. activating tyrosine kinase
✅ Answer: A. binding intracellular receptors and altering gene transcription
Being lipid-soluble, steroid/thyroid hormones enter the cell and act on nuclear receptors → changed gene transcription (slow, prolonged).
Q2
Which hormones are released from the POSTERIOR pituitary?
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A. GH and prolactin
B. ADH and oxytocin
C. TSH and ACTH
D. FSH and LH
✅ Answer: B. ADH and oxytocin
The posterior pituitary stores and releases ADH and oxytocin, made in the hypothalamus. The anterior pituitary makes GH, TSH, ACTH, FSH, LH, prolactin.
Q3
The anterior pituitary is connected to the hypothalamus by:
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A. direct neuronal axons
B. the internal carotid artery
C. the hypophyseal portal blood vessels
D. CSF flow
✅ Answer: C. the hypophyseal portal blood vessels
Hypothalamic releasing/inhibiting hormones travel via the hypophyseal portal vessels to control the anterior pituitary. The posterior lobe gets direct axons.
Q4
Growth hormone promotes linear growth largely by stimulating the liver to release:
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A. insulin
B. IGF-1 (somatomedin)
C. cortisol
D. thyroxine
✅ Answer: B. IGF-1 (somatomedin)
Most growth-promoting effects of GH are mediated by IGF-1 (somatomedin C) from the liver.
Q5
Excess growth hormone in an adult (after epiphyseal closure) causes:
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A. acromegaly
B. gigantism
C. dwarfism
D. cretinism
✅ Answer: A. acromegaly
GH excess before epiphyseal closure → gigantism; after closure → acromegaly (enlarged hands, feet, jaw).
Q6
The main hormone secreted by the thyroid follicular cells is:
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A. T₃ (triiodothyronine)
B. T₄ (thyroxine)
C. calcitonin
D. TSH
✅ Answer: B. T₄ (thyroxine)
T₄ (thyroxine) is the main secreted form; it is converted peripherally to the more active T₃.
Q7
Calcitonin, which lowers plasma calcium, is secreted by the:
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A. thyroid follicular cells
B. parathyroid glands
C. thyroid parafollicular (C) cells
D. adrenal cortex
✅ Answer: C. thyroid parafollicular (C) cells
Parafollicular (B) cells of the thyroid secrete calcitonin, which inhibits osteoclasts (a minor role in humans).
Q8
In the hypothalamic–pituitary–thyroid axis, the sequence is:
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A. TSH → TRH → T₃/T₄
B. T₃/T₄ → TRH → TSH
C. ACTH → TSH → T₃/T₄
D. TRH → TSH → T₃/T₄
✅ Answer: D. TRH → TSH → T₃/T₄
Hypothalamic TRH → pituitary TSH → thyroid T₃/T₄; T₃/T₄ feed back to inhibit TRH and TSH.
Q9
A major action of thyroid hormone is to:
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A. raise the basal metabolic rate and heat production
B. lower the basal metabolic rate
C. lower blood glucose
D. retain sodium
✅ Answer: A. raise the basal metabolic rate and heat production
Thyroid hormone is calorigenic — it raises BMR and heat production, and is essential for growth and CNS development.
Q10
Aldosterone is produced by which zone of the adrenal cortex?
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A. zona fasciculata
B. zona glomerulosa
C. zona reticularis
D. the medulla
✅ Answer: B. zona glomerulosa
Zona glomerulosa → aldosterone (mineralocorticoid). Fasciculata → cortisol; reticularis → androgens.
Q11
The main glucocorticoid, cortisol, is produced by the:
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A. zona glomerulosa
B. zona reticularis
C. zona fasciculata
D. adrenal medulla
✅ Answer: C. zona fasciculata
Zona fasciculata secretes cortisol — it raises blood glucose (gluconeogenesis), is catabolic and anti-inflammatory, and mediates stress.
Q12
The adrenal medulla secretes:
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A. aldosterone
B. cortisol
C. androgens
D. adrenaline and noradrenaline
✅ Answer: D. adrenaline and noradrenaline
The medulla (a modified sympathetic ganglion) releases catecholamines for the fight-or-flight response.
Q13
A patient with central obesity, moon face, hyperglycaemia and hypertension most likely has:
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A. Cushing syndrome (excess cortisol)
B. Addison disease
C. Graves disease
D. diabetes insipidus
✅ Answer: A. Cushing syndrome (excess cortisol)
Cushing syndrome = cortisol excess. Addison = cortisol/aldosterone deficiency (fatigue, hypotension, hyperpigmentation, hyperkalaemia).
Q14
Which is the only hormone that lowers blood glucose, and from which cell?
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A. glucagon, α cell
B. insulin, β cell
C. somatostatin, δ cell
D. cortisol, adrenal cortex
✅ Answer: B. insulin, β cell
Insulin from pancreatic β cells lowers blood glucose (↑uptake via GLUT4, glycogenesis, lipogenesis) — the only hypoglycaemic hormone.
Q15
Glucagon, from the pancreatic α cell, raises blood glucose mainly by:
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A. increasing glucose uptake by muscle
B. stimulating insulin
C. hepatic glycogenolysis and gluconeogenesis
D. inhibiting cortisol
✅ Answer: C. hepatic glycogenolysis and gluconeogenesis
Glucagon drives the liver to break down glycogen and make new glucose, raising blood glucose between meals.
Q16
Which set of hormones all RAISE blood glucose?
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A. insulin, glucagon, cortisol
B. insulin and somatostatin
C. calcitonin and PTH
D. glucagon, cortisol, growth hormone, adrenaline
✅ Answer: D. glucagon, cortisol, growth hormone, adrenaline
Glucagon, cortisol, GH and adrenaline are the counter-regulatory (hyperglycaemic) hormones; only insulin lowers glucose.
Q17
Parathyroid hormone (PTH) acts to:
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A. raise plasma calcium
B. lower plasma calcium
C. raise plasma phosphate
D. inhibit vitamin D
✅ Answer: A. raise plasma calcium
PTH raises plasma Ca²⁺: ↑bone resorption, ↑renal Ca²⁺ reabsorption (↓phosphate), and activation of vitamin D → ↑gut Ca²⁺ absorption.
Q18
Active vitamin D (calcitriol) raises plasma calcium mainly by:
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A. inhibiting osteoclasts
B. increasing intestinal Ca²⁺ absorption
C. increasing renal Ca²⁺ excretion
D. stimulating calcitonin
✅ Answer: B. increasing intestinal Ca²⁺ absorption
Calcitriol's chief action is to increase intestinal absorption of Ca²⁺ (and phosphate).
Q19
Hypocalcaemia causes tetany because low extracellular Ca²⁺:
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A. blocks the Na⁺/K⁺ pump
B. depolarises cells permanently
C. increases the excitability of nerve and muscle membranes
D. stops acetylcholine release
✅ Answer: C. increases the excitability of nerve and muscle membranes
Low Ca²⁺ increases Na⁺-channel excitability → spontaneous nerve/muscle firing → carpopedal spasm (Chvostek/Trousseau signs).
Q20
The hypothalamic–pituitary–adrenal (HPA) axis controlling cortisol is:
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A. TRH → TSH → cortisol
B. GnRH → LH → cortisol
C. GHRH → GH → cortisol
D. CRH → ACTH → cortisol
✅ Answer: D. CRH → ACTH → cortisol
Hypothalamic CRH → pituitary ACTH → adrenal cortisol; cortisol feeds back to inhibit CRH and ACTH.
1Hormone+
A chemical messenger secreted by an endocrine gland (or cell) into the blood, which acts at low concentration on specific target-cell receptors to regulate metabolism, growth, reproduction or homeostasis.
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2Tropic (trophic) hormone+
An anterior-pituitary hormone whose target is another endocrine gland, which it stimulates to grow and secrete — e.g. TSH (thyroid), ACTH (adrenal cortex), FSH/LH (gonads). The target-gland hormone then feeds back negatively.
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3Negative feedback (endocrine axis)+
The dominant control of hormone secretion: the target-gland hormone (e.g. cortisol, T₃/T₄) inhibits the hypothalamic releasing hormone and the pituitary tropic hormone, keeping the hormone level within narrow limits.
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4Insulin+
A peptide hormone from pancreatic β cells; the only hypoglycaemic hormone. It promotes glucose uptake (GLUT4 in muscle/fat), glycogenesis, lipogenesis and protein synthesis — the body's main anabolic, fuel-storage signal.
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5Aldosterone+
The principal mineralocorticoid, from the adrenal zona glomerulosa. It increases Na⁺ reabsorption and K⁺ secretion in the distal nephron, thereby regulating extracellular volume and blood pressure; stimulated by angiotensin II and high K⁺.
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6Parathyroid hormone (PTH)+
The main calcium-raising hormone, from the parathyroid glands. It increases bone resorption, renal Ca²⁺ reabsorption (with phosphate loss) and the renal activation of vitamin D, thereby raising plasma Ca²⁺.
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Essay 1
Describe the relationship between the hypothalamus and the two lobes of the pituitary gland.
10 marks
Anterior pituitary (adenohypophysis)
Connected to the hypothalamus by the hypophyseal portal blood vessels. Hypothalamic releasing/inhibiting hormones (e.g. TRH, CRH, GnRH, GHRH, somatostatin, dopamine) travel in the portal blood to control secretion of the anterior-pituitary hormones: GH, TSH, ACTH, FSH, LH, prolactin.
Posterior pituitary (neurohypophysis)
An extension of the hypothalamus connected by direct neuronal axons. ADH and oxytocin are synthesised in the supraoptic and paraventricular nuclei, transported down the axons, and stored/released from the posterior lobe.
Control
Most axes operate by negative feedback — the target-gland hormone inhibits the hypothalamus and pituitary.
Marking guide (10 marks): anterior — portal vessels + releasing hormones 3 · anterior hormones list 2 · posterior — direct axons 2 · ADH/oxytocin made in hypothalamus 2 · negative feedback 1
Essay 2
Describe the actions of thyroid hormone and the consequences of its over- and under-secretion.
10 marks
Synthesis and axis
Follicular cells make T₄ (and T₃) from iodine + thyroglobulin; T₄ → T₃ peripherally. Axis: TRH → TSH → T₃/T₄, with negative feedback.
Actions
- ↑Basal metabolic rate and heat production (calorigenic).
- Essential for normal growth and especially CNS development.
- Potentiate catecholamines (↑heart rate and contractility).
Hyperthyroidism (e.g. Graves)
↑BMR, weight loss, heat intolerance, tachycardia, tremor, exophthalmos.
Hypothyroidism
Child: cretinism (mental + growth retardation). Adult: myxoedema (cold intolerance, weight gain, slowness). Iodine deficiency → goitre.
Marking guide (10 marks): synthesis + TRH/TSH axis 2 · actions (BMR, growth/CNS, catecholamines) 4 · hyperthyroidism features 2 · hypothyroidism (cretinism/myxoedema) + goitre 2
Essay 3
Describe the hormones of the adrenal cortex and the main actions of cortisol.
10 marks
Three cortical zones
- Zona glomerulosa → aldosterone (mineralocorticoid): ↑renal Na⁺ reabsorption + K⁺ secretion → controls volume/BP.
- Zona fasciculata → cortisol (glucocorticoid).
- Zona reticularis → adrenal androgens (DHEA).
Actions of cortisol
- Gluconeogenesis → raises blood glucose; promotes protein and fat catabolism (provides substrate).
- Anti-inflammatory and immunosuppressive.
- Central to the stress response; permissive for catecholamine action; controlled by the CRH → ACTH → cortisol (HPA) axis.
Clinical
Excess = Cushing syndrome; deficiency = Addison disease.
Marking guide (10 marks): three zones + their hormones 3 · aldosterone action 1.5 · cortisol — gluconeogenesis/catabolic 2 · anti-inflammatory + stress + HPA axis 2.5 · Cushing/Addison 1
Essay 4
Describe how insulin and glucagon regulate blood glucose.
10 marks
Insulin (β cell) — lowers glucose
Released when blood glucose rises. It increases glucose uptake into muscle and fat (GLUT4), and promotes glycogenesis, lipogenesis and protein synthesis (anabolic, fuel storage). It is the ONLY hypoglycaemic hormone.
Glucagon (α cell) — raises glucose
Released when blood glucose falls. It drives hepatic glycogenolysis and gluconeogenesis to release glucose.
Counter-regulation
Cortisol, growth hormone and adrenaline also raise glucose. The insulin:glucagon ratio sets the fed (storage) vs fasting (mobilisation) state.
Clinical
Insulin deficiency (type 1) or resistance (type 2) → diabetes mellitus: hyperglycaemia, glycosuria, osmotic diuresis, and in severe type 1, ketoacidosis.
Marking guide (10 marks): insulin source + actions (lowers glucose, anabolic) 3.5 · glucagon source + actions (raises glucose) 2.5 · counter-regulatory hormones / insulin:glucagon ratio 2 · diabetes 2
Essay 5
Describe the hormonal control of plasma calcium.
10 marks
Normal level
Plasma Ca²⁺ is held at 2.2–2.6 mmol/L because it controls nerve/muscle excitability, clotting and secretion.
PTH (raises Ca²⁺)
From the parathyroids in response to low Ca²⁺: ↑bone resorption, ↑renal Ca²⁺ reabsorption (with phosphate loss), and activation of vitamin D.
Calcitriol / active vitamin D (raises Ca²⁺)
↑Intestinal absorption of Ca²⁺ and phosphate.
Calcitonin (lowers Ca²⁺)
From thyroid C cells; inhibits osteoclasts (minor role in humans).
Disorders
Hypocalcaemia → tetany (↑excitability). Hyperparathyroidism → hypercalcaemia ('stones, bones, groans'). Vitamin D deficiency → rickets/osteomalacia.
Marking guide (10 marks): normal level + importance 1 · PTH actions (raises Ca²⁺) 3 · calcitriol (gut absorption) 2 · calcitonin (lowers Ca²⁺) 2 · disorders (tetany/hyperPTH/vitD deficiency) 2