Q.State whether true or false: a. Gastrointestinal tract, kidney and heart also produce hormones. b. Pars distalis produces six trophic hormones. c. B-lymphocytes provide cell-mediated immunity. d. Insulin resistance results in a disease called diabetes mellitus.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Endocrine Glands And Hormones
Endocrine Glands and Hormones: The Body's Chemical Messengers
Think about how your body coordinates everything that happens inside it. When you run, your heart beats faster, your breathing quickens, and your muscles get more blood. When you're scared, your pupils dilate and your palms sweat. When you eat, your digestive system kicks into gear. How does your body know to do all these things at the right time?
You already know about the nervous system — it works like a telephone network, sending electrical signals along wires (nerves) to specific destinations. But there's another system that works differently. It's like sending a letter through the postal service instead of making a phone call. This is the endocrine system.
The Intuition: Ductless Glands and Chemical Messengers
Most glands in your body have ducts — little tubes that carry their secretions to where they're needed. Sweat glands have ducts that carry sweat to your skin. Salivary glands have ducts that carry saliva into your mouth.
But some glands have no ducts. They release their secretions directly into the bloodstream. These are endocrine glands (from Greek endon = within, krinein = to separate). Their secretions are called hormones (from Greek hormao = to set in motion, to excite).
Here's the key idea: a hormone is a chemical messenger. It's released by one part of the body, travels through the blood, and affects another part of the body that is far away. The hormone doesn't affect every cell it passes — only cells that have the right receptor for it, like a lock that only opens with a specific key.
The word "endocrine" contrasts with "exocrine" — exocrine glands (like sweat glands, salivary glands, digestive glands) have ducts and release their secretions to a surface or cavity. Endocrine glands have no ducts and release hormones into the blood.
The Precise Statement
Endocrine glands are ductless glands that secrete hormones directly into the bloodstream. Hormones are chemical substances that act as messengers, traveling through the blood to target organs or tissues, where they bind to specific receptors and trigger a response. This system provides chemical coordination — a slower but longer-lasting form of control compared to the nervous system.
Endocrine Gland (no duct) → secretes Hormone into blood → hormone travels to Target Organ → binds to Receptor → Response
How It Works: A Concrete Example
Consider the hormone insulin, secreted by the pancreas (an endocrine gland). When you eat a meal rich in carbohydrates, your blood sugar rises. The pancreas detects this rise and releases insulin into the blood. Insulin travels everywhere in your bloodstream, but it only affects cells that have insulin receptors — mainly liver, muscle, and fat cells. These cells respond by taking up glucose from the blood, bringing your blood sugar back down to normal.
Notice the sequence: stimulus (high blood sugar) → gland (pancreas) → hormone (insulin) → target cells (liver, muscle, fat) → response (glucose uptake, lower blood sugar).
Key Properties of Hormones
- Released in tiny amounts — hormones are incredibly potent. A few molecules can trigger a large response.
- Travel via blood — this means they reach every part of the body, but only targets with receptors respond.
- Slow but sustained — nervous system responses happen in milliseconds but fade quickly. Hormonal responses take seconds to minutes but can last for hours or days.
- Specificity — a hormone only affects cells that have the matching receptor. This is why the same hormone can have different effects on different tissues.
A common mistake is to think hormones affect all cells equally. They don't. A hormone is like a radio broadcast — it reaches everyone, but only those tuned to the right frequency (having the right receptor) can hear it.
Why This Matters for Coordination
Your body needs two systems for coordination because they complement each other:
| Nervous System | Endocrine System |
|---|---|
| Electrical signals along nerves | Chemical signals in blood |
| Fast (milliseconds) | Slow (seconds to minutes) |
| Short-lived effect | Long-lasting effect |
| Precise, point-to-point | Broadcast, widespread |
| For immediate actions | For sustained changes |
a. True — the gastrointestinal tract, kidney and heart all produce hormones, alongside the organised endocrine glands.
b. True — the pars distalis of the anterior pituitary produces six trophic hormones (GH, prolactin, TSH, ACTH, LH and FSH).
c. False — it is T-lymphocytes, not B-lymphocytes, that provide cell-mediated immunity. …
Statements (a), (b) and (d) are true, but statement (c) is false because cell-mediated immunity is a T-lymphocyte function, not a B-lymphocyte one.
Going through each statement in turn:
- (a) True. Hormones are not confined to the organised endocrine glands. The gastrointestinal tract, the liver, the kidney and the heart also release hormones from diffuse tissue, and this is explicitly part of the endocrine system.
- (b) True. The pars distalis, or anterior pituitary, produces exactly six hormones: growth hormone, prolactin, thyroid stimulating hormone, adrenocorticotrophic hormone, luteinizing hormone and follicle stimulating hormone. …
Showing the 12 most recent of 13 on this concept.
- AP EAPCET 2026Set ap-2026-05-19-AN1 markMCQQ.Match the following: List-I | List-II A. Cortisol | I. Ejection of milk from breast B. Catecholamines | II. Growth hormone releasing hormone C. Oxytocin | III. Generates anti inflammatory reactions D. Somatocrinin | IV. Increases blood glucose (A) A-III, B-IV, C-II, D-I (B) A-II, B-III, C-I, D-IV (C) A-III, B-IV, C-I, D-II (D) A-III, B-II, C-IV, D-I
›Reveal solutionSolution
Cortisol's hallmark is anti-inflammatory action, catecholamines raise blood glucose in stress response, oxytocin ejects milk, and somatocrinin is GHRH by name — giving A-III, B-IV, C-I, D-II.
Concept and Intuition
Each hormone here has a well-defined, frequently tested signature action. Cortisol (a glucocorticoid from the adrenal cortex) is best known clinically and physiologically for its potent anti-inflammatory and immunosuppressive effects (which is why synthetic corticosteroids are prescribed as anti-inflammatory drugs), distinguishing it here from catecholamines. Catecholamines (adrenaline/noradrenaline from the adrenal medulla) are the classic "fight-or-flight" hormones — among their many roles, a hallmark one is rapidly increasing blood glucose via glycogenolysis to fuel an emergency response. Oxytocin, released from the posterior pituitary, triggers the milk-ejection ("let-down") reflex in lactating mothers by causing contraction of myoepithelial cells around the mammary alveoli — a very specific, unambiguous match. Somatocrinin is simply another name for growth hormone-releasing hormone (GHRH), a hypothalamic hormone that stimulates the anterior pituitary to secrete growth hormone — the name itself ("somato-" = body/growth, "-crinin" = releasing hormone) gives this away directly.
Step-by-Step Solution
- Oxytocin ↔ milk ejection (I): unambiguous, well-known physiological reflex.
- Somatocrinin ↔ GHRH (II): follows directly from its name/definition. …
- AP EAPCET 2026Set ap-2026-05-19-AN1 markMCQQ.Study the following statements regarding hormones and choose the correct statements A) Progesterone and oxytocin are identical in function of maintenance of pregnancy B) Steroid hormones are derivatives of cholesterol. C) Low calcium content in plasma stimulates secretion of calcitonin. D) Cortisol and Thyroxine stimulate RBC production (A) A & C (B) A & D (C) B & D (D) B & C
›Reveal solutionSolution
Of the four hormone statements, only "steroid hormones are cholesterol derivatives" and "cortisol and thyroxine stimulate RBC production" are correct; progesterone/oxytocin are not functionally identical, and calcitonin is released in response to high (not low) blood calcium.
Concept and Intuition
This question strings together several independent endocrinology facts, so each must be checked on its own merits:
- Progesterone maintains the uterine lining/pregnancy; oxytocin instead triggers strong uterine muscle contractions, primarily at parturition (childbirth) and during milk ejection — these are different, not "identical," functions.
- All steroid hormones (glucocorticoids, mineralocorticoids, sex hormones) share cholesterol as their biosynthetic precursor.
- Calcitonin (from thyroid C-cells) is secreted when blood calcium rises, to bring it back down (by inhibiting bone resorption); low calcium instead stimulates parathyroid hormone (PTH), not calcitonin.
- Cortisol and thyroxine both have a general stimulatory influence on erythropoiesis (red blood cell production), in addition to the primary regulator, erythropoietin.
Step-by-Step Solution
- A) Progesterone maintains pregnancy; oxytocin causes contractions (labour) — different roles, not identical. False. …
- AP EAPCET 2025Set ap-2025-05-19-AN1 markMCQQ.Match the following Hormones - Chemical nature A) Insulin I) Steriod B) Estrogen II) Peptide C) Oxytocin III) Amine D) Thyroxine IV) Protein V) Polysaccharide Identify the correct match (A) A-IV, B-I, C-III, D-II (B) A-III, B-II, C-IV, D-V (C) A-IV, B-I, C-II, D-III (D) A-V, B-IV, C-III, D-II
›Reveal solutionSolution
By chemical class: Insulin is a protein, Estrogen is a steroid, Oxytocin is a (small) peptide, and Thyroxine is an amine (tyrosine-derived) hormone.
Concept and Intuition
Hormones are grouped by chemical nature: steroid hormones (derived from cholesterol, e.g., estrogen, testosterone, cortisol), peptide/protein hormones (chains of amino acids, e.g., insulin — a protein made of two polypeptide chains; oxytocin — a small 9-amino-acid peptide), and amine hormones (derived from single amino acids like tyrosine, e.g., thyroxine, adrenaline).
Step-by-Step Solution
- Insulin: built of two polypeptide chains → classified as a protein hormone (IV).
- Estrogen: cholesterol-derived → steroid (I).
- Oxytocin: a short 9-amino-acid chain → peptide (II).
- Thyroxine: a modified tyrosine derivative → amine (III).
- This gives A-IV, B-I, C-II, D-III.
Common Mistakes …
- AP EAPCET 2025Set ap-2025-05-20-AN1 markMCQQ.Match the following. Gland/Hormone: A) Thyroid gland I) Calcitonin; B) Adrenal medulla II) Melatonin; C) Pineal gland III) Thymosin; D) Pancreas IV) Nor epinephrine; V) Glucagon (A) A-I, B-IV, C-II, D-V (B) A-III, B-V, C-V, D-II (C) A-V, B-II, C-IV, D-I (D) A-IV, B-I, C-II, D-III
›Reveal solutionSolution
Matching endocrine glands to one of their hormones: Thyroid–Calcitonin,
Adrenal medulla–Norepinephrine, Pineal gland–Melatonin, Pancreas–Glucagon. Answer:
(A).
Concept and Intuition
Each endocrine gland secretes a characteristic set of hormones. The thyroid gland
secretes thyroxine/triiodothyronine (metabolism regulation) and also calcitonin (calcium
regulation, lowering blood calcium). The adrenal medulla, the inner part of the adrenal
gland, secretes the catecholamines adrenaline and noradrenaline (norepinephrine),
central to the "fight or flight" response. The pineal gland secretes melatonin, which
regulates circadian rhythms. The pancreas, via its islets of Langerhans, secretes both
insulin (from beta cells, lowering blood glucose) and glucagon (from alpha cells, raising
blood glucose).
Step-by-Step Solution
- Thyroid gland → Calcitonin (I) — a hormone that regulates blood calcium levels, distinct from its main thyroid hormones.
- Adrenal medulla → Norepinephrine (IV) — one of its two principal catecholamine secretions.
- Pineal gland → Melatonin (II) — its signature hormone. …
- AP EAPCET 2024Set ap-2024-05-16-FN1 markMCQQ.Match the following: List-1: A. Life saving hormones, B. Hypoglycemic hormone, C. Chief androgen, D. Pancreozymin List-2: I. Cholecystokinin, II. Testosterone, III. Glucocorticoids, IV. Insulin (A) A-III, B-IV, C-II, D-I (B) A-III, B-IV, C-I, D-II (C) A-IV, B-III, C-I, D-II (D) A-I, B-II, C-III, D-IV
›Reveal solutionSolution
Each descriptive nickname maps to one specific hormone: life-saving→glucocorticoids, hypoglycemic→insulin, chief androgen→testosterone, pancreozymin→cholecystokinin.
Concept and Intuition
Several hormones carry descriptive alternate names based on their essential physiological roles:
- Glucocorticoids (like cortisol) are called "life-saving hormones" because they are essential for coping with stress; their absence (as in Addison's disease) is fatal without treatment.
- Insulin lowers blood glucose, so it is the hypoglycemic hormone (opposite of glucagon, the hyperglycemic hormone).
- Testosterone is the principal (chief) androgen produced by the testes.
- Pancreozymin is an older synonym for cholecystokinin (CCK), a gut hormone that also stimulates pancreatic enzyme secretion.
Step-by-Step Solution
- A. Life saving hormones → III. Glucocorticoids. …
- AP EAPCET 2024Set ap-2024-05-17-AN1 markMCQQ.Identify the correct statements regarding hormones. I. Addisons disease is associated with glycosuria and formation of ketone bodies. II. Hydrocortisone and glucagan stimulate gluconeogenesis. III. Somatotropin and somatostatin released from hypothalamus are antagonistic hormones. IV. Vasopressin is a peptide hormone. (A) I, III (B) III, IV (C) I, II (D) II, IV
›Reveal solutionSolution
This tests endocrine facts across several glands; only "hydrocortisone/glucagon stimulate gluconeogenesis" and "vasopressin is a peptide hormone" are correct — II and IV.
Concept and Intuition
Each statement needs to be checked against its specific hormone physiology:
- Addison's disease is caused by adrenal cortex insufficiency (hypocortisolism), producing hypoglycaemia and hypotension — not the hyperglycaemia-linked glycosuria/ketosis seen in diabetes.
- Cortisol (hydrocortisone) and glucagon are both counter-regulatory/catabolic hormones that raise blood glucose by promoting gluconeogenesis.
- Growth hormone (somatotropin) is secreted from the anterior pituitary; only its regulators (GHRH, and inhibitor somatostatin/GHIH) come from the hypothalamus — so lumping both hormones as "hypothalamic" is inaccurate.
- Vasopressin (antidiuretic hormone, ADH) is a small 9-amino-acid peptide hormone.
Step-by-Step Solution
- I: Addison's disease → adrenal insufficiency → hypoglycaemia, not glycosuria/ketone bodies (those relate to diabetes/hyperglycaemia) → FALSE. …
- AP EAPCET 2023Set ap-2023-05-22-AN1 markMCQQ.Identify the correct match of the gland with its respective hormone and its function (A) Carpus luteum - Estrogen - Support pregnancy. (B) Thyroid - Thyroxin - Regulates blood calcium levels. (C) Anterior pituitary – Oxytocin – Contraction of uterus muscles during child birth. (D) Posterior pituitary – Vasopressin - Stimulates reabsorption of water from Distal Convoluted Tubule.
›Reveal solutionSolution
Only the posterior pituitary–vasopressin–DCT water reabsorption pairing is factually accurate; the other three options each mismatch a gland, hormone, or function.
Concept and Intuition
Endocrine physiology pairs specific glands with specific hormones and well-defined physiological actions. Getting these right requires recalling which gland actually secretes which hormone (not merely which is anatomically or functionally "nearby") and precisely what that hormone does downstream.
Step-by-Step Solution
- Option (A): Corpus luteum's main pregnancy-supporting hormone is progesterone, not estrogen — incorrect pairing.
- Option (B): Thyroxine (from thyroid) regulates basal metabolic rate; blood calcium regulation is the job of calcitonin (also from thyroid, but a different hormone) — incorrect pairing.
- Option (C): Oxytocin is synthesized in the hypothalamus but released from the posterior pituitary, not the anterior pituitary — incorrect pairing. …
- AP EAPCET 2022Set ap-2022-07-12-AN1 markMCQQ.Match the following A. Peptide hormones B. Protein hormones C. Amine hormones D. Steroid hormones
- TSH, ACTH 2. ADH, Oxytosin 3. Estrogen, Testosterone 4. Melatonin, Thyroxin (A) A4, B3, C2, D1 (B) A2, B1, C4, D3 (C) A3, B1, C2, D4 (D) A2, B4, C3, D1
›Reveal solutionSolution
By chemical classification: peptide hormones = ADH & oxytocin (2), protein hormones = TSH & ACTH (1), amine hormones = melatonin & thyroxine (4), steroid hormones = estrogen & testosterone (3) — matching option (B).
Concept and Intuition
Hormones are grouped by their chemical structure, which determines their receptor location and mechanism of action:
- Peptide hormones: short chains of amino acids, e.g. ADH (vasopressin) and oxytocin (each just 9 amino acids) — act via cell-surface receptors.
- Protein hormones: larger polypeptide or glycoprotein hormones, e.g. TSH and ACTH (tropic hormones from the anterior pituitary) — also act via surface receptors.
- Amine hormones: derived from single amino acids (tyrosine), e.g. thyroxine and melatonin — thyroxine acts via intracellular/nuclear receptors, melatonin regulates circadian rhythms.
- Steroid hormones: derived from cholesterol, lipophilic, e.g. estrogen and testosterone — act via intracellular receptors, since they can cross the plasma membrane directly.
Step-by-Step Solution
- Assign ADH and oxytocin (small peptides) to "Peptide hormones" — group A = list 2.
- Assign TSH and ACTH (larger protein/glycoprotein tropic hormones) to "Protein hormones" — group B = list 1. …
- AP EAPCET 2022Set ap-2022-07-12-AN1 markMCQQ.Maintenance of water and electrolyte balance is influenced by which hormone? (A) Thymosin (B) Calcitonin (C) Testosterone (D) Thyroid hormones
›Reveal solutionSolution
Beyond regulating metabolic rate, thyroid hormones (thyroxine/triiodothyronine) also help maintain water and electrolyte balance in the body.
Concept and Intuition
Thyroid hormones are best known for controlling the basal metabolic rate (BMR) and supporting normal growth and development, but standard physiology teaching also credits them with additional roles: supporting erythropoiesis (RBC formation) and helping maintain the body's water and electrolyte balance. This makes thyroid hormones the best fit among the given options. Thymosin (from the thymus) primarily governs T-lymphocyte maturation/differentiation (immune function), not water-electrolyte balance. Calcitonin (from the thyroid's parafollicular cells) regulates blood calcium/phosphate levels specifically, not general water-electrolyte balance. Testosterone governs male secondary sexual characteristics and spermatogenesis, not systemic water balance.
Step-by-Step Solution
- Eliminate thymosin — its role is immune (T-cell maturation), unrelated to water/electrolyte balance.
- Eliminate calcitonin — its role is specifically calcium/phosphate regulation, a narrower mineral-balance function, not general water-electrolyte balance.
- Eliminate testosterone — its role is reproductive/secondary sexual characteristics. …
- AP EAPCET 2022Set ap-2022-07-12-FN1 markMCQQ.Steroid hormones are the derivatives of (A) Amino acids (B) Cholesterol (C) Carbohydrates (D) Glycogen
›Reveal solutionSolution
All steroid hormones are biochemically derived from cholesterol.
Concept and Intuition
Hormones are broadly classed by chemical nature: peptide/protein hormones (derived from amino acids), and steroid hormones (derived from cholesterol, a lipid). Steroid hormones share cholesterol's characteristic four-fused-ring structure, modified by different enzymes in different endocrine glands to yield the various steroid hormones (glucocorticoids, mineralocorticoids, sex hormones).
Step-by-Step Solution
- Recall the classification of hormones by chemistry: amino-acid derivatives/peptides vs. steroids (lipid-derived) vs. eicosanoids.
- Steroid hormones specifically originate from cholesterol via enzymatic modification in steroidogenic tissues (adrenal cortex, gonads, placenta). …
- AP EAPCET 2021Set ap-2021-09-03-AN1 markMCQQ.Which one of the following pairs is incorrectly matched? (A) Insulin – Diabetes Mellitus (Disease) (B) Corpus Luteum – Relaxin (Secretion) (C) Glucagon – Beta Cells (Source) (D) Somatostatin – Delta cells (Source)
›Reveal solutionSolution
This tests knowledge of pancreatic islet cell types and their hormone secretions; the error is assigning glucagon to beta cells instead of alpha cells.
Concept and Intuition
The islets of Langerhans contain distinct cell types, each secreting a specific hormone: alpha (α) cells secrete glucagon (raises blood glucose), beta (β) cells secrete insulin (lowers blood glucose), and delta (δ) cells secrete somatostatin (regulates/inhibits both insulin and glucagon release). Getting alpha and beta cells swapped is one of the most common errors in endocrinology questions.
Step-by-Step Solution
- (A) Insulin – Diabetes Mellitus: correct — insufficient insulin action (deficiency or resistance) causes diabetes mellitus.
- (B) Corpus Luteum – Relaxin: correct — the corpus luteum secretes relaxin, which helps relax the pelvic ligaments and cervix around parturition.
- (C) Glucagon – Beta Cells: incorrect — glucagon is secreted by the alpha cells, not beta cells; beta cells secrete insulin. …
- AP EAPCET 2021Set ap-2021-09-06-AN1 markMCQQ.Match the organ in column I to common name in column II? Column I: i) Epinephrine, ii) Testosterone, iii) Glucagon, iv) Atrial natriuretic factor Column II: a) Stimulates in muscle growth, b) Decreases in blood pressure, c) Breakdown of liver glycogen, d) Increases heart beat (A) (i-d), (ii-a), (iii-c), (iv-b) (B) (i-c), (ii-b), (iii-a), (iv-d) (C) (i-b), (ii-d), (iii-c), (iv-a) (D) (i-a), (ii-b), (iii-c), (iv-d)
›Reveal solutionSolution
This tests hormone-function matching; epinephrine raises heart rate, testosterone drives muscle growth, glucagon breaks down liver glycogen, and ANF lowers blood pressure.
Concept and Intuition
Each hormone here has a signature physiological action commonly tested. Epinephrine (adrenaline), released from the adrenal medulla during the "fight-or-flight" response, rapidly increases heart rate and cardiac output to prepare the body for action. Testosterone, the principal male sex hormone from the testes, promotes anabolic effects including skeletal muscle growth and development of secondary sexual characteristics. Glucagon, secreted by pancreatic alpha cells in response to low blood glucose, stimulates glycogenolysis — the breakdown of stored liver glycogen into glucose — raising blood sugar. Atrial natriuretic factor (ANF), released by the cardiac atria in response to increased blood volume/pressure, promotes vasodilation and increased sodium/water excretion, thereby decreasing blood pressure.
Step-by-Step Solution
- Epinephrine → increases heart beat (d), a well-known adrenaline effect on cardiac rate.
- Testosterone → stimulates muscle growth (a), its classic anabolic androgenic effect. …
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