Thyroid

Question 1

Thyroid hormones

Answer 1

Thyroxine (T4)

Triiodothyronine (T3)

Question 2

T4

Answer 2

Thyroxine

Question 3

T3

Answer 3

Triiodothyronine

Question 4

Functions (general) of thyroid hormones

Answer 4

metabolic homeostasis

• affect every tissue
• protein, lipid, carb metabolism
• cell differentiation, growth, development

Question 5

NIS

Answer 5

sodium iodide symporter

Question 6

Thyroid regulation

Answer 6

• transport proteins
• maintain serum levels of thyroglobulin
• peripheral metabolism by deiodinases
• metabolism of iodine
• hypothalamic-pituitary control

Question 7

TSH

Answer 7

thyroid stimulating hormone

-stimulates NIS to accumulate iodine

Question 8

deiodinases

Answer 8

converts T4-T3-T2

Question 9

NIS locations

Answer 9

thyroid, salivary glands, placenta, brain, lactating breast

Question 10

T4 potency

Answer 10

1

Question 11

T4 protein bound

Answer 11

10-20

Question 12

T4 half life

Answer 12

5-7 days

Question 13

T4 amount secreted by thyroid

Answer 13

80-100 micrograms/day

Question 14

T3 potency

Answer 14

10

Question 15

T3 protein bound

Answer 15

1

Question 16

T3 half life

Answer 16

<24 hours

Question 17

T3 secreted by thyroid

Answer 17

6-10 micrograms / day

Question 18

TSH

Answer 18

Thyroid stimulating hormone

• controled by T4 and T3 levels on pituitary
• levels equate to hypo/hyper
• euthyroid = normal

Question 19

Thyroid condition prevelance

Answer 19

hypothyroidism more prevalent than hyper

Question 20

Hypothyroidism symptoms

Answer 20

fatigue
weight gain
cold intolerance
skin dryness
hair dryness
depression
dementia
cramps
edema
bradycardia
constipation

Question 21

Hyperthyroidism

Answer 21

fatigue
weight loss
heat intolerance
hyperhydrosis
nervousness
insomnia
tremor
weakness
menstrual irregularities
palpitations
hyperdefecation

Question 22

Fetal hypothyroidism

Answer 22

low birth weight

congenital cretinism

Question 23

congenital cretinism

Answer 23

growth failure
mental retardation
neurodevelopmental delays

Question 24

iodine levels for cretinism

Answer 24

<20-25 micrograms /day

Question 25

most common malignant tumor of endocrine system

Answer 25

thyroid cancer

Question 26

Thyroid cancer presentation

Answer 26

- painless lump - normal function - routine exam - slow growth

Question 27

Thyroid cancer types

Answer 27

Differentiated | Undifferentiated

Question 28

Differentiated thyroid cancers

Answer 28

papillary (PTC) - 75-85 % | follicular (FTC) 5-15 %

Question 29

Undifferentiated thyroid cancers

Answer 29

Anaplastic Thyroid carcinoma (ATC) | Medullary thyroid carcinoma (MTC)

Question 30

Carcinoma compared to benign nodules

Answer 30

Carcinomas only 5%

Question 31

PTC

Answer 31

Females 3x more likely and in midlife

Question 32

graves disease

Answer 32

most common hyperthyroidism

Question 33

thyroid cancer latency

Answer 33

5-7 years

Question 34

Why does it appear thyroid cancer incidence has increased

Answer 34

surveillance bias

Question 35

iodine uptake depends on

Answer 35

- percent of administers that enters thyroid - size of thyroid - bio half life

Question 36

percent administered that enters thyroid depends on

Answer 36

- amount of stable iodine in diet - age of patient - gland level of function