Q50. Which mineral is needed for the synthesis of the hormone thyroxine?
[SSC MTS, 11 July 2022, Shift 3]
(A) Iron
(B) Cobalt
(C) Calcium
(D) Iodine
Answer: (D) Iodine
Explanation: Thyroid hormones are iodinated molecules derived from tyrosine. Iodine deficiency impairs their synthesis, sometimes producing hypothyroidism and goitre. Using iodised salt is a preventive strategy; iron and calcium are important nutrients but cannot replace iodine in thyroxine.
Q49. An endocrinologist specialises in the study and treatment of disorders of which body system?
[WBCS Mains, Science, 2022]
(A) Teeth
(B) Hormone-secreting glands
(C) Epidemics
(D) Heart
Answer: (B) Hormone-secreting glands
Explanation: Endocrinology concerns hormones, the glands that produce them, and their effects. Specialists diagnose disorders of thyroid function, diabetes, adrenal disease, pituitary problems and reproductive hormones. Endocrine signalling differs from the duct-based secretion of exocrine glands.
Q48. Which of these is an endocrine gland in the human body?
[RRB NTPC CBT I, 26 July 2021, Shift 1]
(A) Salivary
(B) Pituitary
(C) Prostate
(D) Sweat
Answer: (B) Pituitary
Explanation: The pituitary releases hormones into the circulation rather than through a duct. Its anterior lobe produces growth and tropic hormones, whereas its posterior lobe releases hypothalamic oxytocin and vasopressin. Salivary and sweat glands are typical exocrine examples.
Q47. Which gland hangs from the hypothalamus by a stalk and is traditionally called the master gland?
[RRB NTPC CBT I, 16 January 2021, Shift 2]
(A) Pancreas
(B) Thyroid
(C) Adrenal
(D) Pituitary
Answer: (D) Pituitary
Explanation: The pituitary lies below the hypothalamus in the sella turcica of the sphenoid bone. Its stalk, the infundibulum, provides neural and vascular connections. Several anterior pituitary hormones regulate thyroid, adrenal and gonadal endocrine activity.
Q46. Human growth hormone is secreted mainly by which region?
[RRB NTPC CBT I, 19 January 2021, Shift 1]
(A) Posterior pituitary
(B) Anterior pituitary
(C) Thyroid
(D) Pancreas
Answer: (B) Anterior pituitary
Explanation: Somatotroph cells in the anterior pituitary produce growth hormone. It promotes skeletal and soft-tissue growth partly through IGF-1. The posterior pituitary stores and releases oxytocin and vasopressin but does not synthesise growth hormone.
Q45. Undersecretion of growth hormone during childhood is classically associated with dysfunction of which gland?
[RRB NTPC CBT I, 18 January 2021, Shift 2]
(A) Thyroid
(B) Pituitary
(C) Adrenal medulla
(D) Pancreas
Answer: (B) Pituitary
Explanation: Pituitary growth-hormone deficiency during childhood can cause proportionate short stature, sometimes termed pituitary dwarfism in older textbooks. Height depends on many other influences, including genetics, nutrition and thyroid hormones, so not every case of short stature is endocrine.
Q44. Which glands secrete hormones important in the control of blood pressure?
[RRB NTPC CBT I, 19 March 2021, Shift 2]
(A) Adrenal glands
(B) Pituitary glands only
(C) Pancreas only
(D) Pineal gland
Answer: (A) Adrenal glands
Explanation: The adrenal cortex secretes aldosterone, which promotes renal sodium retention and influences blood volume and pressure. The adrenal medulla releases catecholamines, which affect cardiovascular activity. Blood pressure also depends on kidneys, vessels and nervous-system regulation.
Q43. Which hormone promotes strong uterine contractions during childbirth?
[RRB NTPC CBT I, 27 February 2021, Shift 1]
(A) ADH
(B) Oxytocin
(C) Progesterone
(D) Thyroxine
Answer: (B) Oxytocin
Explanation: Oxytocin is synthesised in the hypothalamus and released through the posterior pituitary. During labour, cervical stretch encourages further oxytocin release, strengthening uterine contractions. The hormone also causes milk ejection, whereas prolactin drives milk production.
Q42. Which hormone from a gland in the brain helps regulate the sleep–wake cycle?
[SSC CHSL, 5 August 2021, Shift 1]
(A) Oxytocin
(B) Insulin
(C) Aldosterone
(D) Melatonin
Answer: (D) Melatonin
Explanation: Melatonin is secreted mainly by the pineal gland, with higher output in darkness. Light suppresses its secretion via circadian pathways. Melatonin helps signal biological night and coordinates timing, but sleep itself is controlled by several interacting neural systems.
Q41. Which of the following hormones is produced by the pancreas?
[BPSC 66th Preliminary Examination, 2020]
(A) Thyroxine
(B) Insulin
(C) Melatonin
(D) Gastrin
Answer: (B) Insulin
Explanation: Insulin is produced by beta cells in the pancreatic islets of Langerhans. It reduces blood glucose by promoting cellular uptake and storage of nutrients. The pancreas also produces glucagon and digestive enzymes, so it functions as a mixed gland.
