Week 1 - Intro to Endocrinology

1. What is the endocrine system?

A system of glands/tissues that produce hormones and target cells that respond to them

2. How do endocrine hormones reach their target cells?

Via the circulation

3. What defines an endocrine gland as “ductless”?

Hormones are secreted directly into the bloodstream

4. Who first described the thyroid as a ductless gland?

Galen of Pergamon

5. Which gland did Galen possibly first describe?

The adrenal gland

6. What contribution did Leonardo da Vinci make to endocrinology?

Early anatomical drawings of endocrine organs

7. Who produced early anatomical illustrations of endocrine organs in the 16th century?

Bartolomeo Eustachius

8. What historical observations suggested testes influence male characteristics?

Castrati and eunuchs

9. What was Berthold’s 1849 experiment studying?

The endocrine role of the testes

10. What is a capon?

A castrated cockerel

11. What happened to secondary sex characteristics after testis transplantation?

They were restored

12. What did Berthold’s experiment demonstrate?

Hormones act via the blood

13. Which scientist removed thyroids from monkeys?

Victor Horsley

14. What condition developed after thyroid removal in monkeys?

Myxoedema

15. What symptoms characterise myxoedema?

Hair loss, lethargy, severe hypothyroidism

16. What did Horsley’s work prove about myxoedema?

It is caused by thyroid deficiency

17. Who treated myxoedema using “pink thyroid juice”?

George Murray

18. What was “pink thyroid juice”?

Filtered sheep thyroid extract

19. Which hormone discovery marked the birth of endocrinology as a field?

Secretin

20. Who discovered secretin?

William Bayliss and Ernest Starling

21. What key idea did Starling introduce?

Chemical messengers coordinating organ function

22. What structures form the hypothalamic–pituitary–end organ axis?

Hypothalamus, pituitary, endocrine gland

23. What type of feedback predominates in endocrine axes?

Negative feedback

24. What hormones does the hypothalamus release?

Releasing and inhibitory hormones

25. What is the role of the anterior pituitary?

Secretes trophic hormones

26. What does GHRH stimulate?

Growth hormone release

27. What does somatostatin inhibit?

Growth hormone release

28. What is the main bioactive hormone of the GH axis?

IGF-1

29. Where are GH receptors mainly expressed?

Liver

30. What condition results from GH excess before epiphyseal closure?

Gigantism

31. What condition results from GH excess after epiphyseal closure?

Acromegaly

32. What causes Laron syndrome?

GH insensitivity

33. What is the function of IGF-1?

Mediates growth effects of GH

34. Which axis regulates cortisol secretion?

HPA axis

35. What hypothalamic hormone initiates the HPA axis?

CRH (CRF)

36. What pituitary hormone stimulates the adrenal cortex?

ACTH

37. What type of hormone is cortisol?

Steroid hormone

38. Where is cortisol produced?

Adrenal cortex

39. Which receptor does ACTH bind?

MC2 receptor

40. Which endocrine axis does not directly involve the pituitary?

Renin–angiotensin–aldosterone axis

41. What is a suppression test used to diagnose?

Hormone excess

42. What does failure to suppress hormone levels suggest?

Autonomous secretion

43. Which suppression test is used in suspected Cushing’s syndrome?

Dexamethasone suppression test

44. What is a stimulation test used to diagnose?

Hormone deficiency

45. What does failure to rise hormone levels indicate?

Endocrine insufficiency

46. Which stimulation test assesses adrenal function?

Synacthen (ACTH) test

47. What hypothalamic hormone controls the HPT axis?

TRH

48. What pituitary hormone stimulates the thyroid gland?

TSH

49. What hormones are produced by thyroid follicular cells?

T3 and T4

50. What are the systemic effects of thyroid hormones?

Increased metabolism and growth

51. What hormones define the HPG axis?

GnRH, LH, FSH

52. What are LH and FSH collectively called?

Gonadotropins

53. What are examples of end-organ hormones in the HPG axis?

Testosterone, estradiol

54. What determines timing of puberty?

Activation of the HPG axis

55. What is precocious puberty?

Early activation of the HPG axis

56. What is delayed puberty?

Failure or delay in HPG axis activation

57. What is endocrine signalling?

Hormone signalling via blood

58. How does neural signalling differ from endocrine signalling?

Faster and more localised

59. What is autocrine signalling?

Cell acts on itself

60. What is paracrine signalling?

Cell acts on neighbouring cells

61. What is endocrine signalling?

Hormone acts on distant cells

62. What type of hormone is insulin?

Peptide hormone

63. How are peptide hormones synthesised?

RER → Golgi → vesicles

64. Are peptide hormones water soluble?

Yes

65. Where are peptide hormone receptors located?

Cell surface

66. What second messengers do peptide hormones use?

Intracellular signalling cascades

67. From what precursor are steroid hormones derived?

Cholesterol

68. Are steroid hormones water soluble?

No

69. Where are steroid hormone receptors located?

Inside the cell

70. How do steroid hormones affect cells?

Alter gene transcription

71. What amino acid are catecholamines derived from?

Tyrosine

72. Which tyrosine derivatives act like peptides?

Catecholamines

73. Which tyrosine derivatives act like steroids?

Thyroid hormones

74. What is cortisol binding globulin (CBG)?

Cortisol transport protein

75. What does SHBG bind?

Testosterone and estradiol

76. What is the function of hormone binding proteins?

Transport and protection

77. How do binding proteins affect hormone half-life?

Increase it

78. How do binding proteins affect hormone availability?

Act as a reservoir

79. What type of feedback dominates endocrine axes?

Negative feedback

80. What is the purpose of negative feedback?

Maintain hormonal homeostasis