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NEET ZoologyUpdated 19 Oct 2026

Chemical Coordination and Integration: NEET PYQs and weightage

Chemical Coordination and Integration carries 5.6 of 100 Zoology marks in NEET by past-paper share: 36 of the 648 tagged NEET Zoology PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 8 of 17 Zoology chapters.

Take the 25-question Chemical Coordination and Integration testKey facts ↓All NEET Zoology chapters
5.6/100 Weight in Zoology
4 of 5 Exam importance (4/5, by past-paper share)
36 NEET PYQs
482 Practice questions
390 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Zoology PYQs in the bank (36 of 648), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

Chemical Coordination and Integration: key facts for NEET

16 facts the paper keeps asking, each with how it is asked. Copy it onto one page of your notebook: that page is this chapter's handbook.

  1. Hypothalamus

    Hypothalamus (basal diencephalon) sends releasing and inhibiting hormones to the anterior pituitary through a portal circulation. GnRH stimulates gonadotrophin release, and somatostatin inhibits GH release.

    Asked as: which hypothalamic hormone inhibits GH release, or how hypothalamic hormones reach the anterior pituitary (portal circulation)

  2. Pituitary: pars distalis and pars intermedia

    Pituitary sits in the sella tursica. Pars distalis (anterior pituitary) makes six hormones: GH, PRL, TSH, ACTH, LH and FSH. Pars intermedia makes only MSH.

    Asked as: odd one out among hormones of pars distalis (MSH is from pars intermedia)

  3. Posterior pituitary

    Posterior pituitary (pars nervosa) stores and releases oxytocin and vasopressin. The hypothalamus synthesises both, and they travel down axons to the posterior pituitary.

    Asked as: site of synthesis vs site of release of oxytocin/ADH

  4. GH disorders

    Excess GH in childhood causes gigantism, and too little GH causes pituitary dwarfism. Excess GH in adults, especially middle age, causes acromegaly, which disfigures the face most.

    Asked as: match disorder age GH level

  5. Gonadotrophins (LH and FSH)

    In males, LH drives androgen secretion by the testis, and FSH with androgens regulates spermatogenesis. In females, LH triggers ovulation of the Graafian follicle and maintains the corpus luteum, while FSH drives growth of ovarian follicles.

    Asked as: which gonadotrophin triggers ovulation and maintains the corpus luteum (LH)

  6. ADH and diabetes insipidus

    ADH acts on the distal tubules to reabsorb water and electrolytes. Impaired ADH synthesis or release leads to water loss and dehydration, called Diabetes Insipidus.

    Asked as: deficiency of which hormone causes diabetes insipidus (not insulin)

  7. Pineal and melatonin

    Pineal (dorsal forebrain) secretes melatonin, which regulates the 24-hour diurnal rhythm (sleep-wake cycle, body temperature). It also affects metabolism, pigmentation, the menstrual cycle and defence capability.

    Asked as: hormone controlling the sleep-wake cycle

  8. Thyroid hormones

    Thyroid follicular cells make (thyroxine) and , and iodine is essential for their synthesis. Iodine deficiency causes hypothyroidism and goitre. Hypothyroidism in pregnancy causes cretinism in the baby. Exophthalmic goitre (Graves' disease) is a form of hyperthyroidism.

    Asked as: goitre vs cretinism vs Graves' disease, matched with hypo- or hyperthyroidism

  9. TCT and PTH (calcium control)

    Thyrocalcitonin (TCT, from the thyroid) lowers blood . PTH comes from four parathyroids on the back of the thyroid and is hypercalcemic. PTH raises through bone resorption, renal reabsorption and gut absorption.

    Asked as: name the hypercalcemic hormone (PTH), or which hormone lowers blood (TCT)

  10. Thymus and thymosins

    Thymus (behind the sternum) secretes thymosins. Thymosins drive T-lymphocyte differentiation, giving cell-mediated immunity. Thymosins also promote antibody production, giving humoral immunity. The thymus degenerates in old age, so immunity weakens.

    Asked as: why immune response is weak in the elderly

  11. Adrenal medulla (catecholamines)

    Adrenal medulla secretes adrenaline and noradrenaline (catecholamines), the fight-or-flight hormones. Their effects: pupillary dilation, piloerection and sweating; faster and stronger heartbeat and faster breathing; glycogenolysis, lipolysis and proteolysis.

    Asked as: which is NOT an effect of adrenaline (e.g., pupil constriction)

  12. Adrenal cortex

    Adrenal cortex has three zones: zona glomerulosa (outer), zona fasciculata (middle) and zona reticularis (inner). Cortisol, the main glucocorticoid, is anti-inflammatory, suppresses immunity and stimulates RBC production. Aldosterone, the main mineralocorticoid, retains and water and excretes and phosphate. Cortical underproduction causes Addison's disease.

    Asked as: arrange the cortical layers outer to inner, or which hormone retains (aldosterone)

  13. Pancreas (Islets of Langerhans)

    Pancreas has 1-2 million Islets of Langerhans, making up 1-2% of pancreatic tissue. -cells secrete glucagon, which is hyperglycemic (glycogenolysis and gluconeogenesis in hepatocytes). -cells secrete insulin, which is hypoglycemic (glucose uptake into hepatocytes and adipocytes, and glycogenesis). Prolonged hyperglycemia leads to diabetes mellitus, with glucose in urine and ketone bodies.

    Asked as: which cell secretes which hormone, or hyperglycemic vs hypoglycemic hormone

  14. Gonadal hormones

    Leydig (interstitial) cells of the testis make androgens, mainly testosterone. In the ovary, growing follicles make estrogen, and the corpus luteum after ovulation makes mainly progesterone, which supports pregnancy and forms the milk-storing alveoli.

    Asked as: source of testosterone, or which structure secretes progesterone

  15. ANF and erythropoietin

    The atrial wall of the heart secretes ANF, which dilates blood vessels and lowers BP. Juxtaglomerular cells of the kidney secrete erythropoietin, which stimulates RBC formation.

    Asked as: name the blood-pressure-lowering hormone (ANF), or the source of erythropoietin

  16. GI hormones and mechanism of hormone action

    The GI tract secretes four peptide hormones: gastrin ( and pepsinogen secretion); secretin (water and bicarbonate from the pancreas); CCK (pancreatic enzymes and bile); GIP (inhibits gastric secretion and motility). Hormones on membrane-bound receptors (e.g., peptides) act through second messengers such as cAMP, and . Hormones on intracellular receptors (steroids, iodothyronines) regulate gene expression.

    Asked as: match GI hormone action, or which hormone does not use a second messenger (steroid/thyroid)

Trap

Oxytocin and vasopressin are made in the hypothalamus, not the posterior pituitary, which only stores and releases them. Also, ADH deficiency causes diabetes insipidus, and insulin problems cause diabetes mellitus.

How does NEET ask Chemical Coordination and Integration?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1ZoologyNEET UG PYQHuman Endocrine System
Try right here · No sign-in
Which of the following are not the effects of Parathyroid hormone ? a. Stimulates the process of bone resorption b. Decreases Ca level in blood c. Stimulates reabsorption of Ca by renal tubules d. Decreases the absorption of Ca from digested food e. Increases metabolism of carbohydrates Choose the most appropriate answer from the options given below
Answer key (B) & worked solution

Correct answer: Option B

Parathyroid hormone increases the Ca levels in the blood. PTH acts on bones and stimulates the process of bone resorption (dissolution/ demineralisation). PTH also stimulates reabsorption of Ca by the renal tubules and increases Ca absorption from the digested food. PTH is a hypercalcemic hormone and along with TCT (thyrocalcitonin), it plays a significant role in calcium balance in the body.
Q2ZoologyNEET UG PYQHuman Endocrine System
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R : Assertion A: FSH acts upon ovarian follicles in female and Leydig cells in male. Reason R: Growing ovarian follicles secrete estrogen in female while interstitial cells secrete androgen in male human being. In the light of the above statements, choose the correct answer from the options given below :
ABoth A and R true but R is NOT the correct explanation of A.
BA is true but R is false
CA is false but R is true
DBoth A and R are true and R is the correct explanation of A.
Answer key (C) & worked solution

Correct answer: Option C

LH acts on the Leydig cells in males to produce Androgens (Not FSH)
Q3ZoologyNEET UG PYQHuman Endocrine System
Identify the hormone with its correct matching of source and function.
AMelatonin – Pineal gland – regulates the normal rhythm of sleep-wake cycle
BProgesterone – corpus callosum – secondary sex organs
CAtrial natriuretic factor –ventricular wall – increases the blood pressure
DOxytocin – anterior pituitary – growth and maintenance of mammary glands
Answer key (A) & worked solution

Correct answer: Option A

Oxytocin, produced by posterior pituitary gland functions in parturition. Melatonin is a hormone from the pineal gland that helps regulate biological rhythms such as sleep and wake cycles. It directs the internal clock - the one that allows us to wake up about the same time every morning without an alarm clock. Progesterone secreted by the corpus luteum is a steroid hormone involved in the menstrual cycle, pregnancy and embryogenesis. Atrial natriuretic factor is a powerful vasodilator and a protein hormone, secreted by heart muscle cells.
Q4ZoologyNEET UG PYQHuman Endocrine System
The posterior pituitary gland is not a ‘true’ endocrine gland because _____.
AIt only stores and releases hormones
BIt is under the regulation of hypothalamus
CIt secretes enzymes
DIt is provided with a duct
Answer key (A) & worked solution

Correct answer: Option A

Oxytocin and vasopressin hormones are produced by hypothalamus but stored and are released into the bloodstream via posterior pituitary. Posterior pituitary do not synthesize any hormone that's why it is not a true endocrine gland. Endocrine glands are the ductless glands that synthesize and secrete hormones in blood directly.
Q5ZoologyNEET UG PYQMechanism of Hormone Action
How does steroid hormone influence the cellular activities:
ABinding to DNA and forming a gene-hormone complex
BActivating cyclic AMP located on the cell membrane
CUsing aquaporin channels as second messenger
DChanging the permeability of the cell membrane
Answer key (A) & worked solution

Correct answer: Option A

Steroid hormones directly enter into the cell and bind with intracellular receptors either present in cytoplasm or nucleus and form hormone-receptor complex. This hormone-receptor complex interacts with the genome.
Q6ZoologyNEET UG PYQHuman Endocrine System
Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other?
AParathormone-Calcitonin
BInsulin-Glucagon
CAldosterone-Atrial Natriuretic factor
DRelaxin-Inhibin
Answer key (D) & worked solution

Correct answer: Option D

Relaxin is a protein hormone secreted by placenta. It dilates the cervix and aids in childbirth. Inhibin is secreted from ovaries and inhibits the release of FSH (Follicle stimulating hormone). Parathormone increases blood calcium level by increasing the reabsorption of calcium from the bones. Calcitonin acts on bone and kidneys to reduce blood calcium level. Insulin acts on hepatocytes and adipocytes and increases the uptake of cellular glucose and its utilisation. Thus, it decreases blood glucose level. Glucagon increases blood sugar level by stimulating glycogenolysis (i.e. breakdown of glucose) and gluconeogenesis (synthesis of glucose). Aldosterone maintains the electrolyte balance in the body by reducing the loss of sodium through urine and sweat. Atrial natriuretic factor stimulates excretion of sodium in kidneys.
Q7ZoologyNEET UG PYQHuman Endocrine System
Match List I with List II. List I List II(A)CCK (I)Kidney(B)GIP (II)Heart(C)ANF (III)Gastric gland(D)ADH (IV)PancreasChoose the correct answer from the options given below:
AA–III, B–II, C–IV, D–I
BA–II, B–IV, C–I, D–III
CA–IV, B–II, C–III, D–I
DA–IV, B–III, C–II, D–I
Answer key (D) & worked solution

Correct answer: Option D

List I List II(A)CCK (IV)Pancreas(B)GIP (III)Gastric gland(C)ANF (II)Heart(D)ADH (I)Kidney
Q8ZoologyNEET UG PYQHuman Endocrine System
Fight-or-flight reactions cause activation of
AThe kidney, leading to suppression of renin angiotensin-aldosterone pathway
BThe adrenal medulla, leading to increased secretion of epinephrine and norepinephrine
CThe pancreas, leading to a reduction in the blood sugar levels
DThe parathyroid glands, leading to an increased metabolic rate
Answer key (B) & worked solution

Correct answer: Option B

Epinephrine (adrenaline) and nor-epinephrine (nor-adrenaline) are rapidly secreted by the adrenal medulla in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of fight or flight.

Which topics in Chemical Coordination and Integration carry the most questions?

All 5 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

TopicPYQsPractice questions
Human Endocrine System29353
Introduction to Hormones348
Hormones of Heart, Kidney, and GI Tract329
Mechanism of Hormone Action145
Miscellaneous Examples07

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Chapters either side of Chemical Coordination and Integration by weight

Human Health and Disease Weight 6.9/100Body Fluids and Circulation Weight 6.0/100Breathing and Exchange of Gases Weight 5.2/100Reproductive Health Weight 5.2/100