Chemical Coordination and Integration — NEET Zoology MCQs with answers

Chemical Coordination and Integration is a Class 11 Zoology chapter in the NEET (UG) syllabus. NEET720 has 1,119 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.

Topics covered

Hypothalamo-hypophyseal axis · Hormonal disorders · Adrenal disorders · Placental hormones · Chemical nature of hormones · Other endocrine tissues · Concept of hormone · Water and electrolyte balance · Integration of control systems · Hypothalamus, Pituitary and Pineal · Thyroid, Parathyroid and Thymus · Adrenal, Pancreas and Gonads · Mechanism of Hormone Action · Hormones of Heart, Kidney and Gastrointestinal Tract · Hormones and their Mechanism of Action · Endocrine Glands and Hormones · Parathyroid and Thyroid Gland · Pituitary and Pancreas · Hormone feedback regulation · Hormones of other organs · Calcitonin · Hormone regulation · Numerical - Hormone concentration · Numerical - Hormone half-life · Hormone disorders · Non-endocrine hormones · Feedback control · Diabetes mellitus · Hormone definition · Hormones of Heart and Kidney · Oxytocin · Hormones of the Gastrointestinal Tract · Iodine deficiency · Comparison · Endocrine Glands Overview · Numerical · Osmoregulation and Blood Pressure · Kidney hormones · Testosterone · Stress Response

8 free Chemical Coordination and Integration practice questions with answers

Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.

1. Question 1 · easy · Adrenal, Pancreas and Gonads

   In humans, the adrenal glands are located as:

   • A.One pair, situated at the anterior end of each kidney
   • B.One pair, situated at the posterior end of each kidney
   • C.A single gland situated below the urinary bladder
   • D.One pair, embedded within the renal medulla of each kidney
   Show answer and explanation

   Answer: A. One pair, situated at the anterior end of each kidney

   The adrenal glands are one pair of endocrine glands, each capping the anterior end (superior pole) of a kidney.

   NCERT describes the adrenal glands as one pair, located at the anterior part of each kidney. They are compound glands with a distinct outer cortex and inner medulla, each with different embryonic origin and secretions. Option B reverses the anatomical position; C ignores their paired nature and location; D wrongly places them inside renal tissue rather than as a separate cap-like gland atop it.

   Common mistake: Confusing anterior/posterior position or thinking there is only a single midline gland.

   Key point: Adrenal glands = one pair, capping the anterior end of each kidney (also called suprarenal glands).

2. Question 2 · medium · Adrenal, Pancreas and Gonads

   Adrenaline and noradrenaline are collectively called 'emergency hormones' because they are:

   • A.Secreted only during sleep to regulate basal metabolism
   • B.Secreted in large amounts during any kind of stress, preparing the body for 'fight-or-flight'
   • C.Secreted exclusively in response to low blood glucose to trigger insulin release
   • D.Secreted by the adrenal cortex to suppress the immune response during infections
   Show answer and explanation

   Answer: B. Secreted in large amounts during any kind of stress, preparing the body for 'fight-or-flight'

   Adrenaline and noradrenaline are secreted in large amounts during stress/emergency, readying the body for immediate action — hence 'fight-or-flight' hormones.

   Catecholamines are secreted by the adrenal medulla in large quantities during any kind of stress or emergency (fear, anger, excitement). They increase heart rate, respiration rate, strength of heart contraction, blood flow to skeletal muscles, blood glucose (via glycogenolysis), alertness, and pupillary dilation — collectively preparing the body for immediate physical action. Option A misassigns a circadian role; C confuses this with glucose-triggered insulin release; D wrongly attributes cortex hormone action (immunosuppression) to catecholamines.

   Common mistake: Attributing cortisol's immune-suppressing action to catecholamines.

   Key point: Emergency hormones = adrenaline + noradrenaline, released during stress to prepare for fight-or-flight.

3. Question 3 · easy · Adrenal, Pancreas and Gonads

   Aldosterone, the principal mineralocorticoid, primarily regulates:

   • A.Blood glucose level through gluconeogenesis
   • B.Na+, water and K+ balance in the extracellular fluid via kidney reabsorption
   • C.Basal metabolic rate of the body
   • D.Secondary sexual characteristics in males
   Show answer and explanation

   Answer: B. Na+, water and K+ balance in the extracellular fluid via kidney reabsorption

   Aldosterone regulates Na+, water, and K+ balance in the extracellular fluid by acting on the kidney tubules.

   Aldosterone, the main mineralocorticoid secreted by the adrenal cortex, plays a vital role in the regulation of the levels of Na+, water, and K+ in the extracellular fluid, primarily by promoting Na+ and water reabsorption (and K+ excretion) in the renal tubules. This is distinct from cortisol's role in glucose metabolism (A), thyroid hormones' role in basal metabolic rate (C), and adrenal androgens' mild role in secondary sexual characteristics (D).

   Common mistake: Mixing up aldosterone's electrolyte role with cortisol's metabolic role.

   Key point: Aldosterone = mineralocorticoid = Na+/water/K+ balance via kidney.

4. Question 4 · medium · Adrenal, Pancreas and Gonads

   Apart from glucocorticoids and mineralocorticoids, the adrenal cortex also secretes small amounts of:

   • A.Thyroxine-like iodinated hormones
   • B.Insulin-like peptide hormones
   • C.Melatonin-like indoleamine hormones
   • D.Androgenic steroids (sex corticoids) with mild effects
   Show answer and explanation

   Answer: D. Androgenic steroids (sex corticoids) with mild effects

   The adrenal cortex also secretes small amounts of androgenic steroids (sex corticoids) that have mild effects.

   In addition to glucocorticoids (cortisol) and mineralocorticoids (aldosterone), the adrenal cortex secretes small amounts of androgenic steroids, often called sex corticoids, which have mild effects on the body. This is distinct from thyroid hormones (thyroxine, produced by the thyroid gland), insulin (produced by pancreatic beta cells), and melatonin (produced by the pineal gland) — all wrong-source distractors testing whether students correctly localize hormone-secreting tissue.

   Common mistake: Forgetting the adrenal cortex's minor androgen secretion, or misattributing it to another endocrine gland.

   Key point: Adrenal cortex secretes three classes: glucocorticoids, mineralocorticoids, and small amounts of androgenic steroids.

5. Question 5 · medium · Adrenal, Pancreas and Gonads

   Addison's disease arises due to:

   • A.Hypersecretion of catecholamines from the adrenal medulla
   • B.Insufficiency (hyposecretion) of corticosteroids from the adrenal cortex
   • C.Hypersecretion of growth hormone from the anterior pituitary
   • D.Hyposecretion of insulin from pancreatic beta cells
   Show answer and explanation

   Answer: B. Insufficiency (hyposecretion) of corticosteroids from the adrenal cortex

   Addison's disease results from insufficiency of adrenal cortex hormones (corticosteroids), i.e., hyposecretion of corticosteroids.

   Addison's disease is a condition arising from adrenal cortex insufficiency — hyposecretion of corticosteroids (glucocorticoids and mineralocorticoids). This is distinct from a medulla-related overactivity condition (A), pituitary growth hormone disorders like gigantism/acromegaly (C), and diabetes mellitus caused by insulin hyposecretion from pancreatic beta cells (D). Addison's disease is mentioned at NEET level as a relevant adrenal cortex disorder.

   Common mistake: Confusing Addison's disease with unrelated endocrine disorders due to similar-sounding 'hormone insufficiency' framing.

   Key point: Addison's disease = adrenal cortex hyposecretion (corticosteroid insufficiency), not a medulla, pituitary, or pancreatic disorder.

6. Question 6 · medium · Adrenal, Pancreas and Gonads

   During a sudden sprint to catch a bus, a person's heart rate rises sharply, pupils dilate, and blood glucose level increases within seconds. Which adrenal secretion is most directly responsible for this rapid response?

   • A.Aldosterone, acting on the kidney tubules
   • B.Cortisol, acting via long-term gene transcription
   • C.Adrenaline (and noradrenaline) from the adrenal medulla, acting rapidly on the heart, pupils and liver glycogen stores
   • D.Adrenal androgens, acting on skeletal muscle growth
   Show answer and explanation

   Answer: C. Adrenaline (and noradrenaline) from the adrenal medulla, acting rapidly on the heart, pupils and liver glycogen stores

   The rapid, seconds-scale response of increased heart rate, pupil dilation and blood glucose rise is characteristic of catecholamines (adrenaline/noradrenaline) from the adrenal medulla.

   Adrenaline and noradrenaline act very rapidly (within seconds) via receptor-mediated signalling to increase heart rate, dilate pupils, and trigger glycogenolysis in the liver to raise blood glucose — exactly matching this scenario. Aldosterone and cortisol both act more slowly (aldosterone regulates ongoing electrolyte balance; cortisol largely acts through gene transcription over minutes to hours), and adrenal androgens have mild, non-acute effects. This question tests the ability to connect a described physiological scenario to the correct, fastest-acting hormone.

   Common mistake: Not distinguishing the fast, non-genomic action of catecholamines from the slower genomic action of steroid hormones like cortisol.

   Key point: Catecholamines act within seconds; cortisol acts over a longer genomic timescale — timing is a key clue to hormone identity.

7. Question 7 · medium · Adrenal, Pancreas and Gonads

   Arrange the following events in the correct physiological sequence when a person suddenly encounters a dangerous situation: I. Adrenal medulla releases adrenaline and noradrenaline into the blood. II. Sympathetic nervous system is activated in response to the perceived threat. III. Liver glycogen is broken down (glycogenolysis), raising blood glucose. IV. Heart rate and strength of contraction increase, along with pupillary dilation.

   • A.II → I → IV → III
   • B.I → II → III → IV
   • C.IV → II → I → III
   • D.II → IV → I → III
   Show answer and explanation

   Answer: A. II → I → IV → III

   The correct sequence is: threat perception activates the sympathetic nervous system (II), which stimulates the adrenal medulla to release catecholamines (I), which then produce widespread effects including cardiovascular changes (IV) and glycogenolysis (III).

   On perceiving a threat, the sympathetic nervous system is activated first (II), and its preganglionic fibres directly stimulate the adrenal medulla (a modified sympathetic ganglion) to release adrenaline and noradrenaline into the blood (I). These circulating catecholamines then rapidly increase heart rate, contraction strength and cause pupillary dilation (IV), while also triggering hepatic glycogenolysis to raise blood glucose (III) — cardiovascular effects are typically the fastest, with metabolic glucose effects following. This tests correct causal-temporal ordering of the stress response, not just knowing the individual facts.

   Common mistake: Placing hormone release before its neural trigger, or downstream effects before the hormone that causes them.

   Key point: Stress response order: sympathetic activation → adrenal medulla catecholamine release → cardiovascular effects and glycogenolysis.

8. Question 8 · easy · Adrenal, Pancreas and Gonads

   The adrenal gland is best described as a:

   • A.Compound gland with two distinct endocrine parts, the cortex and the medulla
   • B.Simple exocrine gland with a single secretory epithelium
   • C.Purely neural structure with no hormone secretion
   • D.Single homogeneous endocrine tissue with one type of secretion
   Show answer and explanation

   Answer: A. Compound gland with two distinct endocrine parts, the cortex and the medulla

   The adrenal gland is a compound endocrine gland made of two distinct parts — the outer cortex and the inner medulla — each with its own secretions.

   The adrenal gland is described in NCERT as a compound gland, since it is structurally and functionally composed of two distinct parts: the outer adrenal cortex (steroidogenic, mesodermal origin) and the inner adrenal medulla (catecholamine-secreting, neural crest origin). It is unambiguously endocrine, not exocrine (B is wrong), does secrete hormones (C is wrong), and is not a single homogeneous tissue (D is wrong).

   Common mistake: Treating the adrenal gland as a single uniform tissue rather than two functionally distinct parts.

   Key point: Adrenal gland = compound endocrine gland with two distinct functional parts (cortex + medulla).

Questions about Chemical Coordination and Integration for NEET

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