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Bch 204 > Thyroid 2 > Flashcards

Thyroid 2 Flashcards

1
Q

Types and biosynthesis of thyroid hormones

-Synthesized in the thyroid gland by: ____ , Coupling of ______ molecules and Attaching to ______ protein

A

Iodination

two tyrosine

thyroglobulin

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2
Q

Thyroid gland mostly secretes ____

A

T4

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3
Q 
Peripheral tissues (liver, kidney, etc.) iodinate T3 to T4
T/F
A

F

They deiodinate T4 to T3

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4
Q

___ is the more biologically active thyroid hormone

A

T3

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5
Q

T4 can be converted to rT3 (____ T3) ( an active or inactive form? )

A

reverse

Inactive

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6
Q

Most of T4 is transported in plasma as protein-bound

  • Thyroglobulin-bound (___ %)
  • Albumin-bound (___ %)
  • Transthyretin-bound (__ %)
A

70

25

5

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7
Q

The unbound (free) form of T4 and T3 are biologically ____

A

active

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8
Q

Thyroid hormone action
-Essential for normal maturation and metabolism of all body tissues
T/F

A

T

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9
Q

Thyroid hormone action
Affects the rate of protein, carbohydrate and lipid metabolism
T/F

A

T

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10
Q

Thyroid hormone action

Regulates thermogenesis
T/F

A

T

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11
Q

Hypothyroid children have delayed skeletal maturation, tall stature, delayed puberty
T/F

A

F

Short

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12
Q

Untreated congenital hypothyroidism causes permanent brain damage
T/F

A

T

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13
Q

Hypothyroid patients have low serum cholesterol

T/F

A

F

High

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14
Q

Hypothyroid patients have High cholesterol due to (up or Down?)? regulation of ____ receptors on ___ cells and Failure of sterol ____ via the ___

A

Down

LDL

liver

excretion; gut

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15
Q

Regulation of thyroid hormone secretion

-The _____ axis regulates thyroid secretion

A

hypothalamic-pituitary-thyroid

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16
Q

The hypothalamus senses low levels of T3/T4 and releases _____

A

thyrotropin releasing hormone (TRH)

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17
Q

TRH stimulates the pituitary to produce _____

A

thyroid stimulating hormone (TSH)

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18
Q

TSH stimulates the thyroid to produce _____ until levels return to normal

A

T3/T4

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19
Q

T3/T4 exert _____ feedback control on the ____ and ____ to Control the release of ___ and ___

A

negative

hypothalamus and pituitary

TRH and TSH

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20
Q

High thyroid level _____ TRH and TSH

-Low thyroid levels ——- TRH and TSH to produce more hormone

A

suppress

stimulate

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21
Q

TSH measurement Indicates thyroid status

T/F

A

T

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22
Q

Total T4 or free T4 measurement can be used to Monitor anti-thyroid treatment and thyroid supplement treatment
T/F

A

T

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23
Q

In T4 treatments , TSH may take upto __ weeks to adjust to new level during treatment

A

8

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24
Q

TSH and T4 (total or free) are ensitive, first-line test

T/F

A

T

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25
Q

Some labs only measure TSH as first-line test

T/F

A

T

26
Q

Total T3 or free T3:
*Rise in T3 is dependent of T4
T/F

A

F

It’s independent

27
Q

For earlier identification of T3 thyrotoxicosis

  • Antibodies:
  • Diagnosis and monitoring of autoimmune thyroid disease
  • Hashimoto’s thyroiditis

T/F

A

T

28
Q

Goitre
-Enlarged thyroid gland May be associated with Normal function of thyroid gland
T/F

A

T

29
Q

Causes of goiter

  • ____ deficiency
  • _____ deficiency
  • ____ thyroiditis
  • Congenital ____thyroidism
  • _____’ disease (___thyroidism)
  • ____ cancer
A

Iodine

Selenium

Hashimoto’s

hypo

Grave’s; hyper

Thyroid

30
Q 
Hypothyroidism

-Primary hypothyroidism:Failure of \_\_\_\_

-Secondary hypothyroidism:Failure of the \_\_\_\_ to secrete TSH (\_\_\_) or Failure of the \_\_\_\_\_\_ axis
A

thyroid gland

pituitary; rare

hypothalamic-pituitary-thyroid

31
Q

Hashimoto’s disease causes ____?

Hypo or hyper thyroidism

A

Hypo

32
Q

Radioiodine or surgical treatment of hyperthyroidism can go wrong and lead to ____?

A

Hypo

33
Q

Clinical features of hypothyroidism includes ____ skin

A

Dry

34
Q

Diagnosis
Elevated TSH level confirms hypothyroidism
T/F

A

T

35
Q

Treatment for hypothyroidism
-Patient has to continue treatment for a year
T/F

A

F

For ever

36
Q

Neonatal hypothyroidism

  • Due to ____ defect in thyroid gland of newborns
  • Diagnosed by ____ screening
  • Hormone replacement therapy
  • May cause ____, if untreated
A

genetic

TSH

cretinism

37
Q

Non-thyroidal illness

  • In some diseases, the normal regulation of TSH, T3 and T4 secretion and metabolism is disturbed
  • Most of T4 is converted to ____
  • Causing thyroid hormone deficiency
  • TSH secretion is ____
  • Secretion of T4 and T3 is decreased
A

rT3

suppressed

38
Q

Hyperthyroidism

-Tissues are exposed to high levels of thyroid hormones (______)

A

thyrotoxicosis

39
Q

Causes of hyperthyroidism

  • Graves’ disease
  • _____ goitre
  • Thyroid adenoma
  • Thyroiditis
  • Intake of iodine / iodine drugs
  • Excessive intake of T4 and T3
A

Toxic multinodular

40
Q

Clinical features of hyperthyroidism

  • Weight ___ with ___ appetite
  • Fatigue
  • Palpitation / agitation, tremor
  • Angina, heart failure
  • Diarrhea
A

loss ; normal

41
Q

Sweating / heat intolerance is a symptom of ____thyroidism

A

Hyper

42
Q

Eyelid retraction and lid lag is a feature of ____thyroidism

A

Hyper

43
Q

-Most common cause of hyperthyroidism is ____?

A

Grave’s disease

44
Q

Graves’ disease is an autoimmune disease

T/F

A

T

45
Q

In grave’s disease

Antibodies against _____ on thyroid cells mimic the action of _____ hormone
-Normal regulation of synthesis/control is disturbed

A

TSH receptors

pituitary

46
Q

In grave’s disease

Diagnosis

  • _____ TSH level
  • _____ thyroid hormone level
A

Suppressed

Raised

47
Q

Grave’s disease Confirms primary hyperthyroidism

T/F

A

T

48
Q

Problems in diagnosis of grave’s disease

  • Total serum T4 conc. changes due to changes in ______ level
  • In pregnancy, high estrogens increase ____ synthesis
  • Total T4 will be high
  • Congenital TBG deficiency can also influence results
  • _____ and ____ are first-line tests for thyroid dysfunction
A

binding protein

TBG

Free T4 and TSH

49
Q

Treatment

  • Antithyroid drugs: _____,_____
  • Radioiodine: ______ inhibits T4/T3 synthesis
  • Surgery: ___
A

carbimazole, propylthiouracil

sodium 131I

thyroidectomy

50
Q

Thermogenesis

  • About ___% thermogenesis depends on thyroid
  • It ___eases ATP synthesis and consumption by many possible mechanisms
  • ____ gradient requires ATP to maintain it
  • The gradient is used to transport ___ inside the cell
  • Thyroid reduces Na/K gradient across the cell membrane
  • Causing more nutrient transport in the cell (increasing metabolism)
  • This increases the demand for ATP to maintain the gradient
  • ATP synthesis and consumption is increased that produce heat
  • Thyroid hormones cause increased proton leak into the matrix across the inner mitochondrial membrane
  • Protons are pumped back into the matrix by uncoupling proteins (UCPs) without ATP synthesis
  • This process produces heat
  • The mitochondria of brown adipose tissue contain UCP-1 (thermogenin)
  • Produces heat via uncoupling of electron transport chain and oxidative phosphorylation
A

30

incr

Na/K; nutrients

51
Q

Thyroid regulates metabolism and ATP turnover

T/F

A

T

52
Q

The decrease in TBG levels results in a transient ___ease in the level of free thyroid hormones

A

incr

53
Q

a consequence of increased free thyroid hormone is (inhibition or stimulation ?)of synthesis of thyroid hormones (by ____ feedback).

A

Inhibition

negative

54
Q

during pregnancy, the high level of ____ inhibits _____ and __eases TBG levels.

A

estrogen

hepatic breakdown of TBG

hepatic breakdown of TBG

55
Q

With a higher level of TBG, less thyroid hormone is free and unbound.
T/F

A

T

56
Q

In pregnancy, as a consequence of all these changes, levels of total T4 and T3 are ___eased but levels of free, physiologically active, thyroid hormones are ___eased and the person is said to be “clinically _____.”

A

increased

Normal

euthyroid

57
Q

____ converts T4 to T3 by removing one atom of I2 from the ____ ring of the molecule.

A

5′-iodinase

outer

58
Q

The target tissues also convert a portion of the T4 to reverse T3 (rT3) by removing one atom of I2 from the ___ ring of the molecule

A

inner

59
Q

thyroid hormones inhibit the synthesis of (i.e., upregulate) cardiac β1-adrenergic receptors.
T/F

A

F

They induce it

60
Q

Drooping eyelids is a symptom of _____?

Hypo or hyper thyroidism

A

Hypo

61
Q

The most common cause of hypothyroidism is _____ of the thyroid gland (thyroiditis)

A

auto-immune destruction

62
Q

Ingestion of exogenous thyroid hormones, or _____ hyperthyroidism causes goiter or no goiter??

A

factitious

No goiter

Bch 204 (14 decks)

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