Thyroid 2

Question 1

Types and biosynthesis of thyroid hormones

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

Answer 1

Iodination

two tyrosine

thyroglobulin

Question 2

Thyroid gland mostly secretes ____

Answer 2

T4

Question 3

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

Answer 3

F

They deiodinate T4 to T3

Question 4

___ is the more biologically active thyroid hormone

Answer 4

T3

Question 5

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

Answer 5

reverse

Inactive

Question 6

Most of T4 is transported in plasma as protein-bound

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

Answer 6

70

25

5

Question 7

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

Answer 7

active

Question 8

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

Answer 8

T

Question 9

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

Answer 9

T

Question 10

Thyroid hormone action

Regulates thermogenesis
T/F

Answer 10

T

Question 11

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

Answer 11

F

Short

Question 12

Untreated congenital hypothyroidism causes permanent brain damage
T/F

Answer 12

T

Question 13

Hypothyroid patients have low serum cholesterol

T/F

Answer 13

F

High

Question 14

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

Answer 14

Down

LDL

liver

excretion; gut

Question 15

Regulation of thyroid hormone secretion

-The _____ axis regulates thyroid secretion

Answer 15

hypothalamic-pituitary-thyroid

Question 16

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

Answer 16

thyrotropin releasing hormone (TRH)

Question 17

TRH stimulates the pituitary to produce _____

Answer 17

thyroid stimulating hormone (TSH)

Question 18

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

Answer 18

T3/T4

Question 19

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

Answer 19

negative

hypothalamus and pituitary

TRH and TSH

Question 20

High thyroid level _____ TRH and TSH

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

Answer 20

suppress

stimulate

Question 21

TSH measurement Indicates thyroid status

T/F

Answer 21

T

Question 22

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

Answer 22

T

Question 23

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

Answer 23

8

Question 24

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

T/F

Answer 24

T

Question 25

Some labs only measure TSH as first-line test | T/F

Answer 25

T

Question 26

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

Answer 26

F | It’s independent

Question 27

For earlier identification of T3 thyrotoxicosis - Antibodies: * Diagnosis and monitoring of autoimmune thyroid disease * Hashimoto’s thyroiditis T/F

Answer 27

T

Question 28

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

Answer 28

T

Question 29

Causes of goiter * ____ deficiency * _____ deficiency * ____ thyroiditis * Congenital ____thyroidism * _____' disease (___thyroidism) * ____ cancer

Answer 29

Iodine Selenium Hashimoto’s hypo Grave’s; hyper Thyroid

Question 30

``` Hypothyroidism   -Primary hypothyroidism:Failure of ____   -Secondary hypothyroidism:Failure of the ____ to secrete TSH (___) or Failure of the ______ axis ```

Answer 30

thyroid gland pituitary; rare hypothalamic-pituitary-thyroid

Question 31

Hashimoto’s disease causes ____? | Hypo or hyper thyroidism

Answer 31

Hypo

Question 32

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

Answer 32

Hypo

Question 33

Clinical features of hypothyroidism includes ____ skin

Answer 33

Dry

Question 34

Diagnosis Elevated TSH level confirms hypothyroidism T/F

Answer 34

T

Question 35

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

Answer 35

F | For ever

Question 36

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

Answer 36

genetic TSH cretinism

Question 37

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

Answer 37

rT3 suppressed

Question 38

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

Answer 38

thyrotoxicosis

Question 39

Causes of hyperthyroidism - Graves' disease - _____ goitre - Thyroid adenoma - Thyroiditis - Intake of iodine / iodine drugs - Excessive intake of T4 and T3

Answer 39

Toxic multinodular

Question 40

Clinical features of hyperthyroidism - Weight ___ with ___ appetite - Fatigue - Palpitation / agitation, tremor - Angina, heart failure - Diarrhea

Answer 40

loss ; normal

Question 41

Sweating / heat intolerance is a symptom of ____thyroidism

Answer 41

Hyper

Question 42

Eyelid retraction and lid lag is a feature of ____thyroidism

Answer 42

Hyper

Question 43

-Most common cause of hyperthyroidism is ____?

Answer 43

Grave’s disease

Question 44

Graves' disease is an autoimmune disease | T/F

Answer 44

T

Question 45

In grave’s disease Antibodies against _____ on thyroid cells mimic the action of _____ hormone -Normal regulation of synthesis/control is disturbed

Answer 45

TSH receptors pituitary

Question 46

In grave’s disease Diagnosis - _____ TSH level - _____ thyroid hormone level

Answer 46

Suppressed Raised

Question 47

Grave’s disease Confirms primary hyperthyroidism T/F

Answer 47

T

Question 48

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

Answer 48

binding protein TBG Free T4 and TSH

Question 49

Treatment - Antithyroid drugs: _____,_____ - Radioiodine: ______ inhibits T4/T3 synthesis - Surgery: ___

Answer 49

carbimazole, propylthiouracil sodium 131I thyroidectomy

Question 50

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

Answer 50

30 incr Na/K; nutrients

Question 51

Thyroid regulates metabolism and ATP turnover | T/F

Answer 51

T

Question 52

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

Answer 52

incr

Question 53

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

Answer 53

Inhibition negative

Question 54

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

Answer 54

estrogen hepatic breakdown of TBG hepatic breakdown of TBG

Question 55

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

Answer 55

T

Question 56

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 _____.”

Answer 56

increased Normal euthyroid

Question 57

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

Answer 57

5′-iodinase outer

Question 58

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

Answer 58

inner

Question 59

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

Answer 59

F They induce it

Question 60

Drooping eyelids is a symptom of _____? Hypo or hyper thyroidism

Answer 60

Hypo

Question 61

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

Answer 61

auto-immune destruction

Question 62

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

Answer 62

factitious No goiter