Q10. Which hormone primarily regulates the calcium and phosphate balance of human blood?
[UPSC Civil Services Preliminary Examination 2007]
(A) Glucagon
(B) Growth hormone
(C) Parathyroid hormone
(D) Thyroxine
Answer: (C) Parathyroid hormone
Explanation: Parathyroid hormone increases blood calcium by acting on bone and kidneys and by promoting active vitamin D formation. It also reduces renal phosphate reabsorption, increasing phosphate excretion. Its secretion is governed mainly by circulating ionised calcium.
Q9. Which plant hormone is most associated with senescence and fruit ripening?
[WBCS Preliminary Examination 2007]
(A) Cytokinin
(B) Auxin
(C) Gibberellin
(D) Ethylene
Answer: (D) Ethylene
Explanation: Ethylene is a gaseous plant growth regulator that can accelerate ripening and senescence. Cytokinins tend to delay leaf senescence, auxins commonly support cell elongation and gibberellins promote stem growth and seed germination. This is included as a comparative hormone PYQ.
Q8. What is a principal cardiovascular function of noradrenaline?
[WBCS Preliminary Examination 2005]
(A) Increase blood pressure
(B) Increase urine formation
(C) Increase cellular respiration only
(D) Release adrenaline from the thyroid
Answer: (A) Increase blood pressure
Explanation: Noradrenaline, or norepinephrine, activates adrenergic receptors, particularly alpha receptors in blood vessels, causing vasoconstriction and often raising blood pressure. It functions both as a sympathetic neurotransmitter and as a hormone released by the adrenal medulla.
Q7. Match endocrine organs with hormones:
(A) gonads, (B) pituitary, (C) pancreas, (D) adrenal;
(1) insulin, (2) progesterone, (3) growth hormone, (4) cortisol.
[Chhattisgarh PSC Preliminary Examination 2005]
(A) A-3, B-2, C-4, D-1
(B) A-2, B-3, C-4, D-1
(C) A-2, B-3, C-1, D-4
(D) A-3, B-2, C-1, D-4
Answer: (C) A-2, B-3, C-1, D-4
Explanation: Gonadal tissue produces sex hormones including progesterone; the anterior pituitary secretes growth hormone; pancreatic beta cells release insulin; and the adrenal cortex produces cortisol. Remembering the anatomical source prevents confusion between adrenal cortex and medulla.
Q6. The human hormone insulin is produced principally in which organ?
[Uttar Pradesh Lower Subordinate Preliminary Examination 2004]
(A) Liver
(B) Pancreas
(C) Kidney
(D) Pituitary
Answer: (B) Pancreas
Explanation: Islets of Langerhans in the pancreas contain beta cells that manufacture insulin. When blood glucose rises, these cells increase insulin secretion to aid utilisation and storage of nutrients. The organ also makes glucagon and exocrine digestive enzymes.
Q5. What is thyroxine?
[UPPSC PCS Preliminary Examination 2003]
(A) Vitamin
(B) Hormone
(C) Digestive enzyme
(D) Antibody
Answer: (B) Hormone
Explanation: Thyroxine is a thyroid hormone also called T4 because it contains four iodine atoms. It is converted in many tissues to the more active T3 and plays major roles in metabolic rate, development and temperature regulation.
Q4. Which pancreatic structures produce insulin?
[Uttarakhand UDA/LDA Preliminary Examination 2003]
(A) Islets of Langerhans
(B) Pituitary follicles
(C) Thyroid follicles
(D) Adrenal cortex
Answer: (A) Islets of Langerhans
Explanation: Insulin is produced by beta cells within the pancreatic islets of Langerhans. Other pancreatic islet cell types release glucagon and somatostatin. The islets are endocrine tissue, unlike the nearby digestive-enzyme-producing acinar cells.
Q3. Which hormone is associated with affectionate contact between a mother and infant and helps milk let-down?
[Uttar Pradesh Lower PCS Preliminary Examination 2003]
(A) Insulin
(B) Noradrenaline
(C) Follicle-stimulating hormone
(D) Oxytocin
Answer: (D) Oxytocin
Explanation: Infant suckling stimulates neural pathways that release oxytocin from the posterior pituitary. Oxytocin contracts mammary myoepithelial cells and causes milk ejection. It is also involved in social bonding, although behaviour reflects complex brain processes beyond one hormone.
Q2. Consider:
(1) exercise can increase somatotropin secretion;
(2) testes can produce small amounts of progesterone;
(3) female adrenal glands can contribute to androgen production;
(4) stress reduces cortisol secretion.
Which statements are correct?
[UPSC Civil Services Preliminary Examination 2002]
(A) 1, 2, 3 and 4
(B) 1, 2 and 3 only
(C) 2, 3 and 4 only
(D) 1 and 4 only
Answer: (B) 1, 2 and 3 only
Explanation: Exercise can stimulate growth-hormone release; testes produce small amounts of progesterone, and adrenal glands in females contribute androgen precursors. Stress generally increases, rather than decreases, cortisol through the hypothalamic–pituitary–adrenal axis, so statement four is false.
Q1. Which one of the following is NOT an endocrine gland?
[WBCS Preliminary Examination 2002]
(A) Adrenal cortex
(B) Pituitary
(C) Salivary gland
(D) Thyroid
Answer: (C) Salivary gland
Explanation: Salivary glands pour saliva through ducts into the mouth and are therefore exocrine. Adrenal cortex, pituitary and thyroid release hormones into blood without excretory ducts. The distinguishing feature of an endocrine gland is its route of hormone secretion.
