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Flashcards in endocrine 4 - thyroid Deck (76)
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1
Q

what do the thyroid follicles secrete

A

T3 and T4

2
Q

what do the parafollicular cells secrete

A

calcitonin

3
Q

what is the difference with the resting and the active follicle

A

active is enlarged and more plump, the central area is smaller but still filled with colloid

4
Q

what amino acid and element are needed to make thyroid hormones

A

tyrosine and iodine

5
Q

what are the intermediates to thyroid hormones

A

MIT and DIT

6
Q

how is iodide taken into the cell

A

active transport by Na I pump

7
Q

what is thyroglobulin

A

glycoprotein that contains tyrosine

8
Q

what makes MIT

A

tyr + 1 iodine

9
Q

what makes DIT

A

tyr + 2 iodine

10
Q

what makes T3

A

MIT + DIT

11
Q

what makes T4

A

DIT + DIT

12
Q

how does TSH enhance thyroid hormone synthesis

A

increase Na I pump and increase thyroglobulin synthesis (first 2 steps)

13
Q

what happens to T4 and T3 once they are made in the colloid

A

they are endocyzed from the lumen back into the cell

14
Q

how are T3 and T4 released from thyroglobulin

A

lysosomal enzymes

15
Q

what happens once T3 and T4 are released from thyroglobulin

A

they are secreted into the blood, I- and amino acids recycles

16
Q

which thyroid hormone is secreted more into the blood

A

T4>T3

17
Q

how is T3 and T4 transported in the blood

A

bound to thyroid binding protein

18
Q

which T is more potent

A

T3

T4 is a prohormone

19
Q

what happens to T4

A

it is converted into T3 in peripheral cells and liver

20
Q

where does T3 bind

A

nuclear receptors (fat soluble)

21
Q

what percent is T4 and T3 made

A

90% T4

10% T3

22
Q

which thyroid hormone is a prohormone

A

T4

23
Q

what stimulates TSH

A

TRH

24
Q

where is TRH from

A

hypothalamus

25
Q

where is TSH from

A

pituitary

26
Q

what stimulates T3 and T4 production

A

TSH

27
Q

what negatively inhibits TSH

A

T4 and T3

28
Q

what negatively inhibits TRH

A

T4 and T3

29
Q

how do thyroid hormones act on most tissues

A

change transcription and translation

30
Q

what do thyroid hormones do to metabolism

A

increase

31
Q

what is thyroid hormone role in growth

A

it is required for growth and development

32
Q

what does thyroid hormone do to basal metabolic rate

A

increase

33
Q

what does thyroid hormone do to 02 consumption

A

increase

34
Q

what does thyroid hormone do to heat production

A

increase

35
Q

what does thyroid hormone do to catabolism and what causes this

A

increase (too much T3)

36
Q

what does thyroid hormone do to anabolism and what causes this

A

increase (some T3)

37
Q

what does thyroid hormone do to carbohydrate absorption

A

increase

38
Q

what does thyroid hormone do to carbohydrate utilization

A

increase

39
Q

what does thyroid hormone do to protein breakdown

A

increase

40
Q

what does thyroid hormone do to fat breakdown (lipolysis)?

A

increase

41
Q

what does thyroid hormone do to cholesterol metabolism

A

increase

42
Q

what does thyroid hormone do to serum cholesterol

A

decrease

43
Q

how much thyroid hormone do to protein synthesis

A

small amounts

44
Q

how do thyroid hormones act as for growth and development

A

as tissue growth factors

45
Q

what does thyroid hormone do to GH/IGF1 production

A

increase (GH causes IGF1 production in liver)

46
Q

what does thyroid hormone do to CNS maturation in fetus

A

essential, increase

47
Q

what happens with maternal hypothyroidism to the fetus

A

poor fetal CNS development and mental retardation

48
Q

what does thyroid hormone do to heart rate

A

increase

49
Q

what does thyroid hormone do to heart contractility

A

increase

50
Q

what does thyroid hormone do to BP

A

increase

51
Q

what does thyroid hormone do to sympathetic nervous system

A

potentiate beta2 adrenergic receptors

52
Q

what does thyroid hormone do to women reproduction system

A

necessary for normal function and fertility

53
Q

what is Graves disease (simple definition)

A

overactivity of the thyroid gland

54
Q

what kind of disorder causes graves disease

A

autoimmune

55
Q

explain how graves disease works

A

antibodies to the TSH receptor stimulates thyroid hormone preoduction

56
Q

what happens to basal metabolic rate in graves disease

A

increase

57
Q

what is exophthalmos

A

eyes popping out

58
Q

what disease causes exothalmos

A

graves disease

59
Q

what is hashimotos thyroiditis (simple definition)

A

underactive thyroid gland

60
Q

what kind of disorder causes hashimotos thyroiditis

A

autoimmune

61
Q

how does Hashimotos thyroiditis work

A

thyroid peroxidase (TPO) antibodies destroy thyroid gland to block hormone synthesis

62
Q

what is cretinism

A

growth delay, small body, mental retardation in children

63
Q

which disease causes cretinism in children

A

Hashimoto’s thyroiditis

64
Q

what is myxedema

A

lethargy, like depression

65
Q

which disease causes myxedema

A

Hashimoto’s thyroiditis

66
Q

which disease causes goitre

A

Hashimoto’s thyroiditis and graves disease

67
Q

which disease causes cold intolerance

A

hypothyroidism / Hashimoto’s thyroiditis

68
Q

which disease causes weight gain

A

hypothyroidism / Hashimoto’s thyroiditis

69
Q

which disease causes menorrhagia

A

hypothyroidism / Hashimoto’s thyroiditis

70
Q

what is menorrhagia

A

profuse menstrual flow

71
Q

how is goitre made in hyperthyroidism

A

thyroid stimulating immunoglobulins stimulate the thyroid gland to make the goitre

72
Q

how is goitre made in hypothyroidism

A

low iodine in diet lowers T3 and T4 causing an increase in TSH which causes goitre (no iodine in diet, T4 and T3 remains low)

73
Q

what is the best way to measure thyroid function

A

test TSH levels in blood

74
Q

what is the most common cause of hypothyroidism, goitre, mental retardation and preventible brain damage?

A

iodine deficiency

75
Q

is there low or high TSH in blood in hyperthyroidism

A

low

76
Q

is there low or high TSH in blood in hypothyroidism

A

high