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Chemical Coordination and Integration: questions with answers

Class 11 Biology, Chapter 19 (NCERT). 15 questions by concept, 4 with pictures. Open “Show answer” for the answer and why.

How to teach this chapter · Common misconceptions & worked visual for this chapter

Endocrine coordination, hormone definition, and gland locations

Question 1

Which statement correctly describes what belongs to the endocrine system and how it relates to neural coordination?

  1. (a)Organised glands and hormone-producing cells in organs such as heart and kidney both contribute; endocrine regulation can provide continuing control alongside rapid neural signals.
  2. (b)Endocrine and neural coordination can replace each other because both are always equally rapid and short-lived.
  3. (c)Only neural fibres regulate cells, so hormones do not act as intercellular messengers.
  4. (d)Only organised glands contribute hormones; heart and kidney cells therefore lie outside endocrine coordination.
Show answer

(a) Organised glands and hormone-producing cells in organs such as heart and kidney both contribute; endocrine regulation can provide continuing control alongside rapid neural signals.

The endocrine system includes organised glands and diffuse hormone-producing tissues. Neural coordination is rapid and short-lived, whereas endocrine signalling supports continuing regulation; they act jointly.

Question 2

Which complete statement distinguishes endocrine secretion from exocrine secretion?

  1. (a)Hormones are nutrients released in bulk to supply cellular energy.
  2. (b)An endocrine gland releases hormones through ducts to its target.
  3. (c)Every chemical messenger must be produced only by a neural fibre.
  4. (d)An endocrine gland is ductless, and its hormones are trace, non-nutrient intercellular messengers.
Show answer

(d) An endocrine gland is ductless, and its hormones are trace, non-nutrient intercellular messengers.

Endocrine glands lack ducts. Hormones are non-nutrient chemicals produced in trace amounts that act as intercellular messengers.

Hypothalamus–pituitary control and pituitary hormone functions

Question 3

Which route carries hypothalamic control to the anterior pituitary?

Hypothalamus?
  1. (a)a duct from the thyroid gland
  2. (b)hypothalamic hormones through portal circulation
  3. (c)direct neural regulation through hypothalamic axons
  4. (d)the gastrointestinal tract only
Show answer

(b) hypothalamic hormones through portal circulation

The anterior pituitary is regulated by hypothalamic hormones through portal circulation. The two pituitary parts do not receive hypothalamic control through the same route.

Question 4

What does the posterior pituitary do with ADH?

  1. (a)Makes it
  2. (b)Breaks it down
  3. (c)Changes it into oxytocin
  4. (d)Stores and releases it
Show answer

(d) Stores and releases it

ADH is synthesised by the neurosecretory cells of the hypothalamus. It travels down the axons to the pars nervosa, the posterior pituitary, which stores it and releases it into the blood. The posterior pituitary neither makes ADH nor converts it into oxytocin; oxytocin is a separate hypothalamic hormone stored there as well.

Pineal, thyroid, parathyroid, and thymus regulation

Question 5

In a neck-gland diagram, the ? marks the paired lobes on either side of the trachea joined by an isthmus. Which structure is it?

?
  1. (a)adrenal medulla
  2. (b)parathyroid gland
  3. (c)pineal gland
  4. (d)thyroid gland
Show answer

(d) thyroid gland

The described position identifies the thyroid gland. Parathyroids lie on the posterior thyroid, whereas thyroid lobes flank the trachea.

Question 6

A learner makes the following endocrine claims. Which correction is complete?

ClaimLearner’s account
MelatoninComes from the pituitary
Iodine-deficiency goitreIs hyperthyroidism
ThymosinsOnly make antibodies
  1. (a)Melatonin is pineal; iodine deficiency leads to hypothyroidism with goitre; thymosins mainly support T-lymphocyte differentiation and also promote antibody production.
  2. (b)Melatonin is pineal, but iodine deficiency still indicates hyperthyroidism.
  3. (c)Melatonin and iodine statements are corrected, but thymosins act only through humoral immunity.
  4. (d)Melatonin is still said to be from the pituitary, but the thyroid and thymus corrections are correct.
Show answer

(a) Melatonin is pineal; iodine deficiency leads to hypothyroidism with goitre; thymosins mainly support T-lymphocyte differentiation and also promote antibody production.

Each gland has a distinct product and role. Pineal produces melatonin, iodine deficiency impairs thyroid-hormone synthesis, and thymosins support cell-mediated as well as humoral immune functions.

Gland / conditionCorrect account
PinealProduces melatonin
Iodine deficiencyCan impair thyroid-hormone synthesis and cause hypothyroidism with goitre
Thymus / thymosins (chapter account)Supports T-cell differentiation and immune functions, not only antibodies

Pancreatic glucose homeostasis and diabetes mellitus

Question 7

A learner records the following pancreatic-hormone claims. Which replacement repairs every row?

ClaimLearner’s account
Alpha- and beta-cell hormonesThe two hormones are swapped
InsulinRaises blood glucose
GlucagonPromotes glycogenesis
  1. (a)Alpha–glucagon–glycogenesis–lowers glucose; beta–insulin–uptake/glycogenesis–lowers glucose
  2. (b)Alpha–glucagon–glycogenolysis–raises glucose; beta–insulin–uptake/glycogenesis–raises glucose
  3. (c)Alpha–glucagon–glycogenolysis/gluconeogenesis–raises glucose; beta–insulin–uptake/glycogenesis–lowers glucose
  4. (d)Alpha–insulin–uptake/glycogenesis–lowers glucose; beta–glucagon–glycogenolysis–raises glucose
Show answer

(c) Alpha–glucagon–glycogenolysis/gluconeogenesis–raises glucose; beta–insulin–uptake/glycogenesis–lowers glucose

Alpha cells produce glucagon and beta cells produce insulin. Glucagon promotes glycogenolysis and gluconeogenesis and raises blood glucose; insulin promotes uptake, utilisation and glycogenesis and lowers it.

Pancreatic islet cellsHormoneMain actions in this comparisonBlood-glucose effect
AlphaGlucagonGlycogenolysis and gluconeogenesisRaises
BetaInsulinUptake/utilisation and glycogenesisLowers

Question 8

Deficiency of which hormone can cause diabetes insipidus?

  1. (a)Thyroxine
  2. (b)Insulin
  3. (c)ADH (vasopressin)
  4. (d)Growth hormone
Show answer

(c) ADH (vasopressin)

ADH promotes water reabsorption by the kidneys. Its deficiency reduces water conservation and can cause diabetes insipidus.

Hormones from heart, kidney, and gastrointestinal tissues

Question 9

Which hormone stimulates the secretion of HCl and pepsinogen in the stomach?

  1. (a)CCK
  2. (b)GIP
  3. (c)Secretin
  4. (d)Gastrin
Show answer

(d) Gastrin

Gastrin stimulates gastric glands to secrete HCl and pepsinogen. Secretin stimulates pancreatic water and bicarbonate secretion. GIP inhibits gastric secretion.

Question 10

Which hormone stimulates the pancreas to secrete water and bicarbonate?

  1. (a)GIP
  2. (b)Secretin
  3. (c)CCK
  4. (d)Gastrin
Show answer

(b) Secretin

Secretin acts on the exocrine pancreas and stimulates the secretion of water and bicarbonate ions. Gastrin acts on the stomach, CCK stimulates pancreatic enzymes and bile release from the gall bladder, and GIP inhibits gastric secretion and motility.

Adrenal compartments, stress responses, and corticoid actions

Question 11

A learner says, “The central adrenal cortex secretes adrenaline, and its cortical layers run reticularis–fasciculata–glomerulosa from outside inward.” Which correction is complete?

The learner’s adrenal labelsAn illustrative section repeats the learner’s labels: outer reticularis, then fasciculata, then glomerulosa, with central cortex described as secreting adrenaline. These are claims to audit, not accepted anatomy. QUESTION DIAGRAM The learner’s adrenal labels Learner’s claimed labels · no corrected anatomy shown Reticularis (claimed) Fasciculata (claimed) Glomerulosa (claimed) Cortex; adrenaline (claimed) Every name and role shown belongs to the learner’s claim.
  1. (a)The central tissue is cortex and secretes adrenaline; only the stated layer order needs reversing.
  2. (b)The central tissue is medulla and secretes adrenaline; the surrounding cortex runs glomerulosa–fasciculata–reticularis from outside inward.
  3. (c)The central tissue is medulla and secretes adrenaline; reticularis remains the outermost cortical layer.
  4. (d)The central tissue is medulla, but both medulla and cortex secrete only adrenaline.
Show answer

(b) The central tissue is medulla and secretes adrenaline; the surrounding cortex runs glomerulosa–fasciculata–reticularis from outside inward.

Adrenal medulla is central and produces adrenaline and noradrenaline. The cortex surrounds it, and its layers are glomerulosa, fasciculata, then reticularis from outside inward.

Question 12

A section of an adrenal gland has the central region marked with ?. Which compartment is marked?

?
  1. (a)adrenal medulla
  2. (b)zona fasciculata
  3. (c)adrenal cortex
  4. (d)kidney cortex
Show answer

(a) adrenal medulla

The central region is the adrenal medulla. The medulla is central and the cortex surrounds it.

Gonadal hormone sources and reproductive actions

Question 13

Which comparison correctly represents the scope of androgen and progesterone action?

  1. (a)Androgens affect only visible secondary characters; progesterone otherwise has the stated pregnancy and mammary roles.
  2. (b)Androgens have the stated broad actions; progesterone acts only by ejecting milk from mammary glands.
  3. (c)Androgens act on male reproductive and anabolic functions; progesterone supports pregnancy and mammary alveolar development and secretion.
  4. (d)Androgens support pregnancy, whereas progesterone drives spermatogenesis and anabolic metabolism.
Show answer

(c) Androgens act on male reproductive and anabolic functions; progesterone supports pregnancy and mammary alveolar development and secretion.

Androgens regulate male accessory organs, secondary sexual characters, spermatogenesis, sexual behaviour and anabolic metabolism. Progesterone supports pregnancy and mammary alveolar development and secretion; oxytocin, not progesterone, stimulates milk ejection.

Question 14

A chart assigns androgens to seminiferous tubules and says the corpus luteum mainly secretes estrogen. Which correction fixes both source errors?

  1. (a)Assign androgens to Leydig cells, but keep estrogen as the principal corpus-luteum hormone.
  2. (b)Keep seminiferous tubules as the named androgen source, but assign progesterone to the corpus luteum.
  3. (c)Assign androgens to Leydig cells and progesterone to the corpus luteum; retain growing follicles as the main estrogen source.
  4. (d)Assign androgens to growing follicles and progesterone to Leydig cells.
Show answer

(c) Assign androgens to Leydig cells and progesterone to the corpus luteum; retain growing follicles as the main estrogen source.

The named androgen source is the Leydig or interstitial cells between testicular tubules. Growing follicles mainly secrete estrogens, and the corpus luteum mainly secretes progesterone after ovulation.

Hormone receptor specificity and signal mechanisms

Question 15

Which classification of hormone action routes is correct?

  1. (a)Steroids/iodothyronines—intracellular receptors, but receptor binding itself is the complete final physiological response
  2. (b)Steroid hormones—only membrane receptors and second messengers; protein hormones—intracellular genome regulation
  3. (c)Protein hormones—membrane receptors and second messengers; steroids/iodothyronines—intracellular receptors and genome regulation
  4. (d)Every hormone acts without a receptor because all target cells respond equally
Show answer

(c) Protein hormones—membrane receptors and second messengers; steroids/iodothyronines—intracellular receptors and genome regulation

Peptide, polypeptide and protein hormones normally bind membrane receptors and act through second messengers without entering the cell. Steroid hormones and iodothyronines bind intracellular, mostly nuclear, receptors and regulate gene expression through genome interaction.

Common misconception in Chemical Coordination and Integration

Open full misconception guide →

Does a hormone affect every cell it reaches?

Wrong

Insulin acts on all cells equally because blood carries it everywhere.

Why it feels right. Circulation makes the hormone widely available.

Right

A cell responds according to its receptors and signalling machinery.

Worked example

Target cell
Hormone arrives→Matching receptor binds→Response
Other cell
Hormone arrives→No matching receptor→No receptor-mediated response
Both cells encounter the circulating hormone. The matching receptor allows a specific response.
  1. Hormone molecules pass many cells in the bloodstream.
  2. A target cell with the appropriate receptor can respond when the hormone binds.