153 Guess Objective Questions Endocrinology Course (Zoology MJC-6)

Welcome to this comprehensive exploration of Endocrinology, a crucial branch of physiology and medicine focused on the endocrine system, its hormones, and associated disorders. This course review covers the core units, key learning outcomes, and essential topics, reinforcing understanding through 153 objective questions. The quiz is strategically structured to test knowledge across the full spectrum of hormone regulation, from the Hypothalamus and Pituitary gland (Hypothalamo-hypophysial axis) to peripheral endocrine organs like the Thyroid, Adrenal, and Gonads, and finally, molecular mechanisms of hormone action. Mastering these endocrine system MCQs is fundamental for students and professionals seeking a solid grasp of hormonal control in maintaining homeostasis and addressing clinical scenarios. [Image of Hypothalamic-Pituitary-Adrenal Axis Diagram]

Endocrinology Objective Quiz: Test Your Hormone Regulation Knowledge

Unit-1: Introduction to the Endocrine System and Hormone Classification

1. Cushing's disease is caused by hyperactivity of:

• (a) GH
• (b) Thyroxin
• (c) Insulin
• (d) Glucocorticoids

2. Which hormone possesses anti-insulin effect? (increases blood glucose)

• (a) Glucocorticoids
• (b) Calcitonin
• (c) Oxytocin
• (d) Aldosterone

3. Hypoparathyroidism causes:

• (a) Convulsions and tetany (due to hypocalcemia)
• (b) Nervousness and wasting
• (c) Upset in metabolism
• (d) Nervousness and hyperactivity

4. Failure or reduced insulin production causes:

• (a) Diabetes mellitus
• (b) Diabetes insipidus
• (c) Addison's disease
• (d) Cushing's disease

5. Table salt is often iodised for certain areas to prevent:

• (a) Scurvy
• (b) Goiter (due to iodine deficiency)
• (c) Acromegaly
• (d) Rickets

6. Hypothalamus controls the production of pituitary hormones:

• (a) ACTH, GH, ACTH, TSH
• (b) LH, ACTH, TSH
• (c) ACTH, GH, TSH (via Releasing/Inhibiting hormones)
• (d) FSH and Progesterone

7. Facial hair occur in some women due to the effect of:

• (a) UV radiation
• (b) temperature
• (c) Hormones (excess Androgens)
• (d) Pollution

8. Reabsorption of water in distal parts of kidney tubules/urine concentration is controlled by:

• (a) Vasopressin/ADH
• (b) Oxytocin
• (c) Calcitonin
• (d) Relaxin

9. Pineal gland produces:

• (a) Glucagon
• (b) Aldosterone
• (c) Cortisone
• (d) Melatonin

10. Diabetes insipidus is caused by hyposecretion of:

• (a) Insulin
• (b) Vasopressin (ADH)
• (c) Oxytocin
• (d) thymosin

11. Endocrine gland for combatting emergency is:

• (a) Adrenal cortex
• (b) Adrenal medulla (Epinephrine/Norepinephrine)
• (c) Pancreas
• (d) Parathyroid

12. Gluconeogenesis (glucose formation from non-carbohydrates) is strongly controlled by:

• (a) Corticosterone
• (b) Thyroxin
• (c) Cortisol (the primary glucocorticoid)
• (d) All the above

13. Effect of thyroxin on BMR (Basal Metabolic Rate) is:

• (a) Increase
• (b) Decrease
• (c) Uncertain
• (d) No effect

14. Glucagon is produced by:

• (a) Peptic cells
• (b) Oxyntic cells
• (c) Alpha ($\alpha$) cells of Islets of Langerhans
• (d) Beta ($\beta$) cells

15. Primary Female sex-hormone is:

• (a) Estrogen (specifically Estradiol)
• (b) Androgen
• (c) Insulin
• (d) Adrenalin

16. Pancreatic secretion is stimulated mainly by:

• (a) Secretin
• (b) Cholecystokinin-Pancreozymin (CCK is the potent stimulator)
• (c) Duocrinin
• (d) Enterogastrone

17. Neurohypophysis (Posterior Pituitary) secretes:

• (a) Vasopressin and growth hormone
• (b) Oxytocin and estrogen
• (c) Vasopressin (ADH) and oxytocin (released, but synthesized in hypothalamus)
• (d) Vasopressin and estrogen

18. Urine of the would-be-mother contains (used for pregnancy tests):

• (a) Progesterone
• (b) FSH
• (c) Luteinizing hormone
• (d) Chorionic gonadotropin (hCG)

19. Adrenal cortex produces:

• (a) Adrenalin (medulla)
• (b) Epinephrine (medulla)
• (c) Aldosterone (cortex - mineralocorticoid)
• (d) Calcitonin (thyroid)

20. Which activity is disturbed by the degeneration of parathyroid gland:

• (a) Growth
• (b) Calcium concentration (PTH regulates $\text{Ca}^{2+}$)
• (c) Potassium concentration
• (d) Sodium concentration

21. Gastric secretion is stopped by hormone:

• (a) Enterogastrone (now known to be CCK and Secretin primarily)
• (b) Gastrin (stimulates)
• (c) Pancreozymin
• (d) Cholecystokinin

22. Testosterone is produced by:

• (a) Sertoli cells (support sperm)
• (b) Leydig cells (interstitial cells)
• (c) Oxyntic cells
• (d) Pituitary gland

23. Hormone secreted during child birth (to relax pubic symphysis) is:

• (a) Thyroxin
• (b) Relaxin
• (c) Progesterone
• (d) Glucocorticoid

24. Effect of prolactin hormone is on:

• (a) Liver
• (b) Pancreas
• (c) Mammary glands (milk production)
• (d) Bones

25. Dwarfism is due to:

• (a) Absence of insulin
• (b) Hyposecretion of GH during childhood
• (c) Hyposecretion of GH during adult stage
• (d) Excessive secretion of adrenalin

Unit-2: Hypothalamo-Hypophysial System and Pituitary Hormones

26. Ovulation is stimulated by:

• (a) LH (Luteinizing Hormone surge)
• (b) FSH
• (c) Estrogen
• (d) Progesterone

27. Hormone having stimulatory effect on heart (increased heart rate/force) is:

• (a) Thyroxin
• (b) Gastrin
• (c) Glucagon
• (d) Adrenalin (Epinephrine)

28. Glucagon produced by $\alpha$-cells of islets of Langerhans:

• (a) Converts glucose to glycogen
• (b) Converts glycogen to glucose (Glycogenolysis)
• (c) Decreases concentration of glucose in blood
• (d) None of these

29. Diabetes mellitus means:

• (a) Decrease of sugar in blood
• (b) Increase of sugar in urine
• (c) Increase of sugar in blood (Hyperglycemia)
• (d) Both (a) and (b)

30. Least amount of iodine in water affect to metamorphosis of tadpole of frog:

• (a) Accelerated
• (b) Delayed
• (c) Stopped (Thyroid hormone is essential)
• (d) Not affected

31. Blood calcium is increased by administration of:

• (a) Glucagon
• (b) Thyroxin
• (c) Parathormone (PTH)
• (d) Calcitonin (decreases $\text{Ca}^{2+}$)

32. Melanocyte stimulating hormone (MSH) is secreted by pituitary:

• (a) Anterior lobe
• (b) Median lobe (Pars Intermedia)
• (c) Posterior lobe
• (d) Not any particular lobe

33. Function of enterogastrone is:

• (a) Regulation of bile flow
• (b) Stimulation of pancreatic flow
• (c) Inhibition of gastric secretion
• (d) Stimulation of gastric secretion

34. Function of thymus is:

• (a) Immunity (T-cell maturation via Thymosin)
• (b) Growth
• (c) Formation of RBCs
• (d) Emergency hormone

35. Vasopressin (ADH) performs:

• (a) Muscle contraction (Vasoconstriction)
• (b) Increases blood pressure
• (c) Decreases blood pressure
• (d) Both (a) and (b) (Vascular effects)

36. Pituitary gland occurs in:

• (a) Brain (Sella Turcica of sphenoid bone)
• (b) Gonads
• (c) Pancreas
• (d) Trachea

37. Progesterone is secreted by:

• (a) Corpus luteum
• (b) Thyroid
• (c) Thymus
• (d) Testis

38. Diabetes is a disease in which urine contains:

• (a) Salt
• (b) Sugar (Glucose)
• (c) Fat
• (d) Protein

39. Thyroxin is a:

• (a) Vitamin
• (b) Enzyme
• (c) Hormone
• (d) Excretory product

40. Insulin is secreted by:

• (a) Pituitary
• (b) Adrenals
• (c) Thyroid
• (d) Islets of Langerhans ($\beta$-cells)

41. In hormone action, if receptor molecules are removed from target organ, the target organ will:

• (a) Continue to respond to hormone
• (b) Not respond to hormone (Receptors are essential for binding)
• (c) Continue to respond but requires higher concentration
• (d) Continue to respond but in the opposite way

42. Which endocrine gland stores its secretion in extracellular spaces (colloids) before discharging into blood:

• (a) Testis
• (b) Pancreas
• (c) Thyroid
• (d) Adrenal

43. $\text{Ca}^{2+}$ level is controlled by:

• (a) Thyroid
• (b) Hypothalamus
• (c) Pituitary
• (d) Thyroid (Calcitonin) and parathyroids (PTH)

44. Which one is not secreted by pituitary:

• (a) Thyroxin (Secreted by Thyroid)
• (b) FSH
• (c) GH
• (d) ACTH

45. Iodine is present in the secretion of:

• (a) Adrenal
• (b) Thyroid (Thyroxine/$\text{T}_{3}$/$\text{T}_{4}$)
• (c) Pancreas
• (d) Pituitary

46. Which is correct:

• (a) Glucagon and insulin are secreted by same cells
• (b) Glucagon and insulin are secreted by different cells
• (c) Glucagon ($\alpha$) and insulin ($\beta$) are secreted by different cells and have opposite effect (antagonistic)
• (d) None of the above

47. Which gland is often referred in connection with AIDS (due to immune system role):

• (a) Thymus (T-cell maturation)
• (b) Thyroid
• (c) Adrenal
• (d) Pancreas

48. A temporary endocrine gland formed in ovary after ovulation is:

• (a) Corpus uteri
• (b) Corpus albicans (degenerated corpus luteum)
• (c) Corpus callosum
• (d) Corpus luteum

49. Pineal body develops from:

• (a) Dorsal part of diencephalon
• (b) Ventral part of diencephalon
• (c) Ventral side of cerebellum
• (d) Lateral side of cerebrum

50. Metamorphosis in tadpole of Frog is accelerated by:

• (a) Calcium
• (b) Thyroid hormone
• (c) Low pH
• (d) Salinity of water

Unit-3: Peripheral Endocrine Glands (Thyroid, Adrenal, Pancreas)

51. The anterior pituitary hormone that does not stimulate another endocrine gland is:

• (a) Thyrotrophin (TSH)
• (b) Adrenocorticotrophin (ACTH)
• (c) Somatotrophin (GH - acts directly on tissues/liver, not a major endocrine gland)
• (d) Gonadotrophin (FSH/LH)

52. Which of the following is not a chemical messenger?

• (a) Hormone
• (b) Pheromone
• (c) Acetylcholine (Neurotransmitter/messenger)
• (d) Enterokinase (An enzyme)

53. Occurrence of Leydig's cells and their secretion is related to:

• (a) Ovary and oestrogen
• (b) Liver and cholesterol
• (c) Pancreas and glucagon
• (d) Testis and testosterone

54. Iodine taken in diet is stored and concentrated in:

• (a) Liver cells
• (b) Thyroid cells
• (c) Muscle cells
• (d) Brain cells

55. Benedicts reagent test is conducted to confirm the presence of:

• (a) Polysaccharides
• (b) Lipid
• (c) Reducing sugar (e.g., Glucose in urine for Diabetes)
• (d) Protein

56. The primary target organ of aldosterone action is:

• (a) Liver
• (b) Pancreas
• (c) Kidney (Distal tubules and collecting ducts)
• (d) Heart

57. Neurohypophysis (Posterior Pituitary) releases:

• (a) Vasopressin and estrogen
• (b) Vasopressin and growth hormone
• (c) Vasopressin (ADH) and oxytocin
• (d) Oxytocin and estrogen

58. A person with diabetes mellitus does not secrete enough:

• (a) Sugar
• (b) Insulin
• (c) Glucagons
• (d) Epinephrine

59. Which of the following does not secrete any major hormone?

• (a) Ovary
• (b) Testis
• (c) Spleen
• (d) Pancreas

60. Which of the Islets of Langerhans cells secrete insulin?

• (a) Alpha cells (Glucagon)
• (b) $\gamma$-cells (Not standard)
• (c) Beta ($\beta$) cells
• (d) D-cells (Somatostatin)

61. Secretion of progesterone from corpus luteum is induced by:

• (a) LTH (Prolactin, supports function)
• (b) FSH
• (c) LH (Luteinizing Hormone)
• (d) STH (GH)

62. Diabetes insipidus is caused due to hyposecretion of:

• (a) Insulin (causes D. Mellitus)
• (b) Glucagon
• (c) Oxytocin
• (d) Vasopressin (ADH)

63. Aldosterone mainly acts to retain which ions?

• (a) $\text{Na}^{+}$ ions
• (b) $\text{K}^{+}$ ions (excretes)
• (c) $\text{Ca}^{++}$ ions
• (d) $\text{Mg}^{++}$ ions

64. Acromicria (small extremities, often used synonymously with dwarfism) is caused due to insufficient secretion of:

• (a) Thyroxine
• (b) Calcitonin
• (c) Somatotropin (GH)
• (d) Parathormone

65. Acromegaly is caused due to:

• (a) Hypersecretion of GH in adult
• (b) Hypersecretion of GH in children (Gigantism)
• (c) Hyposecretion of GH in adult
• (d) Hyposecretion of GH in children (Dwarfism)

66. Diabetes Mellitus is caused due to the hyposecretion/resistance of a hormone from:

• (a) Adenohypophysis
• (b) Neurohypophysis
• (c) Islets of Langerhans (Insulin)
• (d) Interstitial cells of Leydig

67. Which one is responsible for bringing about the increase in the basal metabolic rate?

• (a) Testosterone
• (b) Prolactin
• (c) Glucagon
• (d) Thyroxine

68. Myxoedema occurs on account of:

• (a) Hyperthyroidism
• (b) Hypothyroidism (in adults)
• (c) Hypoglycemia
• (d) Hyperglycemia

69. Chromaffin tissue is the characteristic feature of:

• (a) Thyroid
• (b) Adrenal cortex
• (c) Neurohypophysis
• (d) Adrenal Medulla

70. Oestrogen is secreted primarily by:

• (a) Leydig's Cells
• (b) Adrenal Cortex (small amount)
• (c) Graafian follicles (Ovary)
• (d) All of the above

71. Adrenal medulla secretes:

• (a) Aldosterone (cortex)
• (b) Epinephrine (Adrenaline)
• (c) Adrenaline (Epinephrine)
• (d) Calcitonin (thyroid)

72. Testosterone is secreted by:

• (a) Sertoli cells
• (b) Acinar cells
• (c) Leydig's cells
• (d) Follicular cells

73. Adrenaline increases:

• (a) Heart beat
• (b) Blood pressure
• (c) Heart beat and Blood pressure
• (d) None of them

74. The tidal volume in a normal man at rest is:

• (a) 0.5 L (500 ml)
• (b) 1.2 L
• (c) 2.5 L
• (d) 4.9 L

75. All the hormones of adrenal cortex are synthesized from:

• (a) Tyrosine
• (b) Glycoproteins
• (c) Cholesterol (Steroid hormones)
• (d) Fats

Unit-3: Peripheral Endocrine Glands (Gonads, Pineal, Thymus) and Disorders

76. Melatonin is secreted by:

• (a) Pineal body
• (b) Hypothalamus
• (c) Thyroid
• (d) Pituitary

77. Gigantism and Acromagaly are due to:

• (a) Hypothyroidism
• (b) Hyper Thyroidsm
• (c) Hyper Pituitarism (excess GH)
• (d) Hypo Pituitarism

78. The neurons of a person with diabetes mellitus do not produce sufficient:

• (a) ATP (due to impaired glucose uptake)
• (b) Fatty acids
• (c) Enzymes
• (d) Steroids

79. Thyroxine is important in the control of:

• (a) Cellular metabolic rates (BMR)
• (b) Diabetes mellitus
• (c) Mitochondrial respiration
• (d) Calcium uptake

80. Which of the following hormones is a modified amino acid?

• (a) Prostaglandin
• (b) Estrogen (Steroid)
• (c) Epinephrine (Catecholamine)
• (d) Progesterone (Steroid)

81. The primary target organ of aldosterone action is:

• (a) Liver
• (b) Pancreas
• (c) Kidney
• (d) Heart

82. Which amino acid is the precursor for the thyroid hormones $\text{T}_{3}$ and $\text{T}_{4}$?

• (a) Tryptophan
• (b) Lysine
• (c) Tyrosine
• (d) Histidine

83. All adrenal steroids originate from:

• (a) Progesterone
• (b) Calcitonin
• (c) Cholesterol
• (d) Parathyroid hormone

84. Which of the following is an example of a local chemical mediator (often paracrine or autocrine)?

• (a) Insulin
• (b) Oxytocin
• (c) Histamine
• (d) All of the above

85. Mature ovarian follicles burst (Ovulation) under the influence of:

• (a) FSH
• (b) Estrogens
• (c) LH (Luteinizing Hormone surge)
• (d) Progesterone

86. Hormone responsible for diabetes insipidus is:

• (a) Insulin
• (b) Glucagon
• (c) Anti-diuretic hormone (ADH/Vasopressin) deficiency/resistance
• (d) Aldosterone

87. Vasopressin is related with (its main renal function):

• (a) Water reabsorption/concentration (of urine)
• (b) Fast digestion
• (c) Slow heart beat
• (d) Slow respiration

88. Names of which set are used for a single hormone:

• (a) Secretin, Gastrin and Enterokinin
• (b) Thyroxin, Oxytocin and Secretin
• (c) Testosterone, LTH and GTH
• (d) ADH, Vasopressin and Pitressin

89. Impairment in the synthesis of dopamine by the brain is a major causative factor for the disorder:

• (a) Parkinson's disease
• (b) Addison's disease
• (c) Cushing's syndrome
• (d) Goiter

90. One of the following hormones is an amino acid derivative

• (a) Epinephrine (Tyrosine derived)
• (b) Norepinephrine (Tyrosine derived)
• (c) Thyroxine (Tyrosine derived)
• (d) All of them

91. The most active mineralocorticoid hormone is

• (a) Cortisol
• (b) Aldosterone
• (c) 11-Deoxycorticosterone
• (d) Corticosterone

92. Name the hormone, predominantly produced in response to fight, fright and flight

• (a) Thyroxine
• (b) Aldosterone
• (c) Epinephrine (Adrenaline, from adrenal medulla)
• (d) ADH

93. The hormone essentially required for the implantation of fertilized ovum and maintenance of pregnancy

• (a) Progesterone
• (b) Estrogen
• (c) Cortisol
• (d) Prolactin

94. Insulin is secreted:

• (a) by suprarenal gland which controls heart beat
• (b) by thyroid gland and controls growth
• (c) by pituitary gland and controls reproduction
• (d) by islet of Langerhans and controls level of sugar in blood

95. Which of the following increases blood pressure and heart beat:

• (a) Gastrin
• (b) Thyroxin
• (c) Adrenalin (Epinephrine)
• (d) Secretin

96. Which gland has the highest amount of iodine (for hormone synthesis):

• (a) Thyroid
• (b) liver
• (c) thymus
• (d) muscles

97. Maturation of gonads is influenced by:

• (a) GH
• (b) ACTH
• (c) LH
• (d) FSH & LH (Gonadotropins)

98. One is secreted by pituitary gland (released by posterior pituitary):

• (a) glucagon
• (b) thyroxine
• (c) aldosterone
• (d) oxytocin

99. One set of diseases is caused by the hypersecretion of hormones:

• (a) cretinism (Hypo-Thyroid) and diabetes (Hypo-Insulin)
• (b) rickets and diabetes
• (c) mongolism and cretinism
• (d) gigantism (Hyper-GH) & toxic goiter (Hyper-Thyroid)

100. Conn's disease is associated with:

• (a) hyposecretion of thyroid
• (b) hypersecretion of thyroid
• (c) hypersecretion of mineralocorticoids (Primary Aldosteronism)
• (d) hyposecretion of mineralocorticoids

Unit-4: Molecular Endocrinology and Hormone Action

101. Somatostatin (Growth Hormone Inhibiting Hormone) is secreted by:

• (a) $\alpha$-cells of islet of Langerhans (Glucagon)
• (b) $\delta$-cells of islet of Langerhans
• (c) $\beta$-cells of islet of Langerhans (Insulin)
• (d) ant. pituitary gland

102. Brain sand (corpora arenacea) is found in:

• (a) pituitary
• (b) adrenal
• (c) pineal
• (d) thymus

103. ADH (Antidiuretic Hormone) is released by:

• (a) ant. pituitary
• (b) post. pituitary
• (c) thyroid
• (d) adrenal

104. STH (Somatotrophic Hormone = GH) is secreted by:

• (a) pituitary (anterior lobe)
• (b) thyroid
• (c) adrenal
• (d) pineal

105. Enterogasterone:

• (a) stimulates gastric glands
• (b) stimulates glands of small intestine
• (c) stops gastric secretion (inhibits motility/acid)
• (d) stimulates gall bladder

106. One of the following does not secrete any major hormone:

• (a) stomach (Gastrin)
• (b) intestine (Secretin, CCK)
• (c) testis (Testosterone)
• (d) spleen

107. Goiter (enlargement) is associated with:

• (a) pituitary
• (b) parathyroid
• (c) suprarenal
• (d) thyroid

108. Androgens are:

• (a) male sex hormones
• (b) female sex hormones
• (c) enzymes
• (d) none of these

109. Secretin hormone is secreted by:

• (a) oesophagus
• (b) duodenum (part of small intestine)
• (c) pancreas
• (d) liver

110. Reabsorption of water in the kidneys is controlled by:

• (a) Oxytocin
• (b) Vasopressin (ADH)
• (c) TSH
• (d) ACTH

111. Progesterone is secreted by:

• (a) corpus callosum
• (b) corpus albicans
• (c) corpus luteum
• (d) corpus uteri

112. Carbohydrate metabolism (glucose uptake/storage) is primarily regulated by:

• (a) thyroxine
• (b) calcitonin
• (c) insulin
• (d) adrenalin

113. Estrogen is secreted by:

• (a) male spleen
• (b) thymus
• (c) ovary (follicles/corpus luteum)
• (d) pituitary

114. Male hormones (testosterone) are secreted by:

• (a) pituitary gland
• (b) thyroid
• (c) interstitial cells of testis (Leydig cells)
• (d) prostate gland

115. Female hormone involved in maintaining pregnancy is called:

• (a) androgens
• (b) progesterone
• (c) estrogen
• (d) glucocorticoids

116. Gonadotrophin hormones (FSH, LH) are secreted by:

• (a) posterior part of thyroid
• (b) adrenal cortex
• (c) cells of Leydig
• (d) adenohypophysis (Anterior Pituitary)

117. Metabolic rate is controlled by:

• (a) thyroid (Thyroxine)
• (b) pituitary (indirectly)
• (c) heart
• (d) parathyroid

118. Function of vasopressin (ADH) is:

• (a) arterial constriction
• (b) to increase blood pressure
• (c) to increase reabsorption of water in uriniferous tubules
• (d) all these

119. If the blood pressure of a person is decreased then which of the following hormones will be beneficial for him (due to vasoconstriction/cardiac stimulation):

• (a) thyroxine
• (b) adrenaline
• (c) growth hormone of pituitary
• (d) insulin

120. Diabetes excess sugar excretion is due to:

• (a) hypersecretion of thyroxine
• (b) hypersecretion of adrenalin
• (c) hyposecretion of vasop-ressin (causes D. Insipidus)
• (d) hyposecretion of insulin (causes D. Mellitus)

121. Most pituitary hormones (e.g., GH, TSH, FSH, LH, ACTH, Prolactin) are chemically:

• (a) steroids
• (b) some are proteins and some are steroids
• (c) proteins (Peptides/Glycoproteins)
• (d) proteins or carbohydrates

122. Which of the following is not directly under the control of pituitary (Adrenal Medulla is controlled by nervous system):

• (a) adrenal cortex (ACTH)
• (b) adrenal medulla
• (c) thyroid (TSH)
• (d) testis (FSH/LH)

123. Spermatogenesis (formation of sperm) is controlled primarily by:

• (a) luteinizing hormone (acts on Leydig cells)
• (b) follicle stimulating hormone (acts on Sertoli cells)
• (c) luteotrophic hormone (Prolactin)
• (d) vasopressin

124. One major similarity between enzymes and hormones is:

• (a) both are proteins (some hormones are steroids)
• (b) both are used repeatedly (hormones are consumed/degraded)
• (c) both are functional in minute quantity
• (d) both become active at a certain pH

125. Most significant growth hormone (GH/STH) is secreted by:

• (a) adrenal
• (b) ant. pituitary
• (c) post. pituitary
• (d) thyroid

126. Hormone is secreted for calcium and phosphorus metabolism by:

• (a) thyroid (Calcitonin)
• (b) parathyroid (Parathormone - strongest influence)
• (c) thymus
• (d) pancreas

127. ACTH is secreted by:

• (a) pituitary (anterior lobe)
• (b) adrenal medulla
• (c) adrenal cortex
• (d) thyroid

128. Glucagon is secreted by:

• (a) $\alpha$-cells of pancreas
• (b) $\beta$-cells of pancreas
• (c) adrenal cortex
• (d) adrenal medulla

129. Hyposecretion of thyroid gland in adult causes:

• (a) cretinism (in children)
• (b) myxedema
• (c) Addison's disease (Adrenal)
• (d) sterility

130. Chemical nature of insulin is:

• (a) protein (Peptide hormone)
• (b) steroid
• (c) carbohydrate
• (d) fat

131. One is secreted by testis:

• (a) progesterone
• (b) testosterone
• (c) TSH
• (d) insulin

132. Growth hormone is secreted by:

• (a) bone
• (b) pituitary (anterior lobe)
• (c) thyroid
• (d) adrenal

133. Co-ordinating system of body is:

• (a) blood circulatory system
• (b) nervous system
• (c) endocrine system
• (d) nervous and endocrine systems (Neuroendocrine regulation)

134. Antidiuretic hormone (ADH) is produced from:

• (a) Kidney
• (b) Hypothalamus (Supraoptic and Paraventricular nuclei)
• (c) anterior pituitary
• (d) posterior pituitary (released, not produced)

135. Which of the following is secreted by the pituitary?

• (a) TSH releasing hormone (Hypothalamus)
• (b) Somatotropin (GH, Anterior Pituitary)
• (c) ACTH releasing hormone (Hypothalamus)
• (d) Somatostatin (Hypothalamus/Pancreas - inhibits GH)

136. The hormone that increases the blood calcium level and decreases its excretion by kidney is (Note: PTH increases blood Ca, but also increases excretion. Calcitonin decreases blood Ca):

• (a) Parathormone (Increases Ca, but also increases Phosphate excretion)
• (b) Thyroxine
• (c) Calcitonin (Decreases blood Ca by inhibiting osteoclasts, leading to less excretion)
• (d) Insulin

137. Which of the following is produced from adrenal cortex?

• (a) Testosteron
• (b) Aldosterone (Mineralocorticoid)
• (c) Adrenalin (Medulla)
• (d) Progesterone

138. The corpus luteum produces

• (a) Prolactin
• (b) Oxytocin
• (c) Progesterone
• (d) Aldosterone

139. Which one of the following is an endocrine as well as an exocrine gland?

• (a) Adrenal medulla
• (b) Parathyroid
• (c) Thyroid
• (d) Pancreas (Exocrine: Digestive juices; Endocrine: Insulin/Glucagon)

140. Addison's disease is due to

• (a) hyposecretion of adrenal cortex (Cortisol/Aldosterone deficiency)
• (b) hypersecretion of adrenal cortex
• (c) hyposecretion of adrenal medulla
• (d) hypersecretion of adrenal medulla

141. Cretinism is due to

• (a) deficiency of thyroid in children (Congenital Hypothyroidism)
• (b) deficiency of thyroid in adults (Myxoedema)
• (c) over secretion of thyroid in children
• (d) oversecretion of thyroid in adults

142. Acromegaly is due to oversecretion of

• (a) GH in children (Gigantism)
• (b) GH after adolescence
• (c) ACTH
• (d) Thyroid in adults

143. FSH (Follicle Stimulating Hormone) from anterior pituitary in males causes:

• (a) secretion of testosterone (LH function)
• (b) secretion of progesterone
• (c) stimulation of spermatogenesis (via Sertoli cells)
• (d) stimulation of corpus luteum (LH function)

144. Oxytocin is released by:

• (a) Hypothalamus (Synthesized here)
• (b) Anterior lobe of pituitary
• (c) Middle lobe of pituitary
• (d) Posterior lobe of pituitary (Released from here)

145. Cushing's disease is due to oversecretion of hormones from:

• (a) Pituitary (ACTH-producing tumor)
• (b) Adrenal cortex (Primary hypercortisolism/syndrome)
• (c) Thyroid
• (d) Adrenal medulla

146. Diabetes insipidus is due to failure of secretion of (or action of):

• (a) Insulin
• (b) ADH (Vasopressin)
• (c) Aldosterone
• (d) thyroid

147. Which cells of pancreas produce insulin?

• (a) $\beta$ cells
• (b) $\alpha$ cells
• (c) Leydig cells
• (d) Interstitial cells

148. Which of the following endocrine glands produces the hormones that are similar to chemicals produced by sympathetic nervous system?

• (a) Pituitary
• (b) Thyroid
• (c) Parathyroid
• (d) Adrenal medulla (Epinephrine/Norepinephrine are catecholamines)

149. Corticotropin releasing hormone (CRH) stimulates the release of

• (a) Adrenalin
• (b) TSH
• (c) Cortisol
• (d) ACTH (Adrenocorticotropic Hormone, from pituitary)

150. The hormone which is synthesized in the hypothalamus but released by the pituitary is:

• (a) FSH
• (b) LH
• (c) ADH (Vasopressin)
• (d) GH

151. Increased glucose synthesis by break down of fats and amino acids (gluconeogenesis) is predominantly due to

• (a) Glucagon (mobilizes glucose, but primary gluconeogenic is C.)
• (b) Insulin
• (c) Glucocorticoids (Cortisol)
• (d) Thyroid

152. Bulging of eyes (exophthalmos); increased BMR, B.P. and heart rate are symptoms of

• (a) Cretinism
• (b) Myxoedema
• (c) Goitre
• (d) Exophthalmic goitre (Grave's disease/Hyperthyroidism)

153. The following hormone is not a gonadotropin hormone (directly controlling gonads):

• (a) ACTH (Adrenocorticotropic Hormone)
• (b) FSH
• (c) LH
• (d) Prolactin (Lactation/Luteotropic)

This extensive 153 objective questions endocrinology quiz serves as a robust self-assessment tool, covering all major glands and hormone actions critical to the endocrine system. Successfully answering these hormone regulation quiz questions demonstrates a foundational understanding of complex feedback loops, glandular function, and common endocrine disorders such as Diabetes Mellitus, Addison's disease, and Acromegaly. Regular practice with these MCQs is invaluable for reinforcing theoretical knowledge and preparing for examinations that demand high precision in differentiating between hyper- and hyposecretion effects, steroid vs. non-steroid hormone action, and the roles of specific hormones like insulin, thyroxine, and cortisol. Mastery here is key to excelling in the broader field of hormonal physiology.

Endocrinology Course Overview: Outcomes, Units, and Key Topics

Endocrinology is the study of internal secretions (hormones) and their actions on metabolism, growth, reproduction, and behaviour. The course is typically structured to provide a comprehensive understanding of the chemical messengers that coordinate activity across the body's systems. Key learning outcomes include the ability to classify hormones, delineate the hypothalamic-pituitary axis, describe the functional histology and pathophysiology of peripheral endocrine glands, and explain the molecular mechanisms by which hormones exert their effects on target cells.

Unit-1: Introduction to the Endocrine System

Overview & Scope

This unit sets the stage by defining the endocrine system, contrasting it with the nervous system, and introducing the concept of neuroendocrine regulation. Students learn the different types of cell-to-cell communication (autocrine, paracrine, endocrine, neurocrine).

Hormone Classification

Hormones are classified based on their chemical structure—peptides/proteins (e.g., Insulin, GH), steroids (e.g., Cortisol, Testosterone), amino acid derivatives (e.g., Thyroxine, Epinephrine)—and their synthesis, transport, and metabolism.

The endocrine system, with its network of glands, secretes hormones directly into the bloodstream to regulate distant target organs, maintaining the body's delicate internal balance.

Unit-2: Hypothalamo-Hypophysial System

Central to hormone regulation is the Hypothalamo-Hypophysial axis, a complex feedback system that controls many peripheral glands.

1. Structure and Function of the Hypothalamus: Focuses on the production of releasing and inhibiting hormones (e.g., GnRH, TRH) and the synthesis of posterior pituitary hormones (Oxytocin and ADH).
2. Pituitary Gland (Master Gland): Detailed study of the structure of the Adenohypophysis (Anterior Pituitary) and Neurohypophysis (Posterior Pituitary), including their unique blood supply.
3. Pituitary Hormones and Regulation: Examination of Anterior Pituitary hormones like GH (Growth Hormone), Prolactin, ACTH, TSH, FSH, and LH, and Posterior Pituitary hormones ADH (Vasopressin) and Oxytocin.
4. Hormonal Dysfunction: Understanding disorders like gigantism, dwarfism, and acromegaly (GH imbalance), and diabetes insipidus (ADH hyposecretion).

Unit-3: Peripheral Endocrine Glands and Pathophysiology

This forms the bulk of the clinical applications, covering the vital peripheral glands.

Key Peripheral Gland Topics:

• Thyroid: Synthesis, storage, and release of $\text{T}_{3}$/$\text{T}_{4}$ (BMR regulation) and Calcitonin (Calcium regulation). Disorders include Goiter, Cretinism, and Myxoedema.
• Parathyroid: Parathyroid Hormone (PTH) and its role in increasing blood calcium levels. Hypoparathyroidism leads to tetany.
• Adrenal Glands: The Cortex (Glucocorticoids like Cortisol, Mineralocorticoids like Aldosterone) and Medulla (Catecholamines like Epinephrine). Disorders include Cushing’s Syndrome and Addison’s Disease.
• Islets of Langerhans (Pancreas): $\alpha$, $\beta$, and $\delta$ cells and their secretions Glucagon, Insulin, and Somatostatin. Focus on the opposing actions of Insulin and Glucagon in glucose homeostasis, leading to Diabetes Mellitus.
• Gonads (Testis/Ovary): Hormones like Testosterone, Estrogen, and Progesterone, their control by pituitary gonadotropins (FSH, LH), and their roles in reproduction and secondary sexual characteristics.

The unit emphasizes the consequences of both hypersecretion and hyposecretion, providing essential context for the endocrinology objective questions encountered in the quiz.

Unit-4: Molecular Endocrinology: Hormone Action Mechanisms

This advanced unit explores how hormones communicate with their target cells, a crucial aspect of hormone physiology.

Hormone Receptors and Signaling

Hormone receptors, which are highly specific proteins, can be located either on the cell membrane or intracellularly. The location dictates the hormone's mechanism of action. Students learn about the principles of receptor binding and signal transduction.

Mechanism of Steroid Hormones

Steroid and Thyroid hormones (lipophilic) cross the cell membrane and bind to intracellular receptors (cytoplasmic or nuclear), forming a hormone-receptor complex that acts as a transcription factor, directly affecting gene expression. This is a slower, but more sustained, form of action.

Mechanism of Non-Steroid Hormones

Peptide/Protein hormones (hydrophilic) bind to cell surface receptors, triggering an intracellular cascade. This involves second messengers like cAMP, $\text{IP}_{3}$/DAG, and $\text{Ca}^{2+}$, leading to rapid cellular responses like enzyme activation or ion channel opening.

Regulation of Hormone Action

The unit concludes by discussing how hormone action is finely tuned, including negative and positive feedback loops, up-regulation, and down-regulation of receptors, ensuring precise control over body functions.

Compact Endocrinology FAQ

Q1: What is the main difference between hormones and pheromones?

A: Hormones are internal chemical messengers secreted into the bloodstream, acting on distant target cells within the same organism. Pheromones are external chemical messengers secreted to the outside, acting on other individuals of the same species (e.g., for attraction or alarm).

Q2: Why is the hypothalamus-pituitary axis considered the control center?

A: The hypothalamus produces releasing and inhibiting hormones that regulate the secretion of the anterior pituitary. In turn, the anterior pituitary hormones regulate major peripheral endocrine glands (thyroid, adrenal cortex, gonads). This hierarchical control is essential for systemic regulation.

Q3: Name the three chemical classes of hormones.

A: Hormones are broadly classified as Peptide/Protein hormones (e.g., Insulin), Steroid hormones (e.g., Cortisol), and Amino Acid Derivatives (e.g., Thyroxine, Epinephrine).

Q4: What is a second messenger in hormone action?

A: A second messenger is an intracellular signaling molecule (like cAMP or $\text{IP}_{3}$) released when a non-steroid hormone (the 'first messenger') binds to a cell surface receptor, relaying the signal from the membrane to the cell's interior to elicit a response.

Key Takeaways for Endocrinology Course Mastery

To succeed in endocrinology units, focus on understanding the interconnectedness of the glands via feedback mechanisms. Memorizing individual hormones and their effects is only the first step. True mastery comes from knowing the cascade of events—from hypothalamic releasing factors to peripheral gland secretion—and the resulting physiological changes. Pay special attention to clinical manifestations of hormonal imbalances, as these often illustrate the hormones' functions in a dramatic way. The molecular mechanisms differentiate hormone types and explain their characteristic speeds of action, which is vital for clinical therapeutics.

Conclusion

Endocrinology is a dynamic and essential field that bridges basic science and clinical medicine. The course content, encompassing glandular structure, hormone synthesis, action mechanisms, and pathophysiology, provides a framework for understanding nearly every physiological process. By diligently engaging with the material and utilising resources like the endocrine system MCQs provided here, students can build a solid foundation in hormone regulation. This knowledge is not only critical for academic success but also for appreciating the subtle, yet powerful, chemical symphony that governs life.