Thyroid 1

Question 1

Thyroid hormones SYNTHESIS
-dependent on iodine
T/F

Answer 1

T

Question 2

Thyroid hormones SYNTHESIS

DEPENDENT ON TYROSINE
T/F

Answer 2

T

Question 3

THYROGLOBULIN is synthesized _____cellularly at ___ surface OF follicular cells and stored in _____

Answer 3

extra

luminal

FOLLICULAR LUMEN

Question 4

Effects of Iodine
-during iodine deficiency, the hormone synthesis is impaired
T/F

Answer 4

T

Question 5

Effects of Iodine

excess iodine inhibits synthesis

T/F

Answer 5

T

Question 6

Thyroid hormone secretions

-with ____ stimulation ,____ brings the _____ back into the ____ to be degraded into ___ and ____

Answer 6

TSH

endocytosis

thyroglobulin

follicular cells

T3 and T4

Question 7

Thyroid hormone binding

• __% of thyroid hormone in the blood is bound
• it could be to thyroxine-____
• thyroxine- ______ (——-)
• _____

Answer 7

99

binding globulin

binding prealbumin; transthyretin

albumin

Question 8

about ____ times as much as is secreted and degraded in a single day(buffer)

Answer 8

three

Question 9

T4 binds better than T3

T/F

Answer 9

T

Question 10

Thyroid hormones effects

• ___eases bmr
• ___eases heat production and oxidative metabolism
• ___eases responsiveness of heart

Answer 10

incr

incr

incr

Question 11

Thyroid hormone is parasympathomimetic

T/F

Answer 11

F

sympathomimetic

Question 12

Thyroid hormone is essential for normal growth of skeletal system , CNS ,ANS

T/F

Answer 12

T

Question 13

Thyroid hormone has a permissive effect on ____ hormone ,_____ factors etc

Answer 13

growth

Insulin-like growth

Question 14

Thyroid hormone is not involved in development of nervous system and adult activity
T/F

Answer 14

F

Question 15

Metabolic effects of thyroid hormones

(1) Calorogenic effect : influences _____ and availability of ____
(2) Carbohydrate metabolism: ___eased glucose absorption from gut , glycogenolysis,gluconeogenesis, glucose oxidation , etc
(3) Lipid metabolism: lipo____ in adipocytes in coordination with blood glucose levels

Answer 15

tolerance to cold

ATP

incr

genesis

Question 16

THYROID HORMONES CONTROL FUEL METABOLISM

GLYCOGENESIS

• Glycogen is a (straight or branched?) polymer of ____ stored in the ____ and ___ cells
• highly regulated by _____

Answer 16

branched

glucose

muscle

liver

insulin

Question 17

Glycogenesis synthesis is by a seperate pathway from glycogenolysis

T/F

Answer 17

T

Question 18

GLYCOGENOLYSIS

• breakdown of glycogen stores into ______
• hormonally controlled by _____,____,____,and____

Answer 18

glucose

glucagon, epinephrine, norepinephrine, and glucocorticoids

Question 19

Glycogenolysis regulates blood glucose between meals

T/F

Answer 19

T

Question 20

Glycogenolysis is suppressed by thyroid hormone

T/F

Answer 20

F

Question 21

GLUCONEOGENESIS

• precursors are __and ___ carbon compounds Through ______
• controlled by ____ and aided by ____ hormone
• main precursor includes alanine and other AA

Answer 21

3 and 4

fructose phosphate

glucagon

thyroid

Question 22

PROTEIN DEGRADATION

• usually balanced by _____
• can be enhanced by ____ and ____ hormones leading to gluconeogenesis

Answer 22

protein synthesis

glucagon

thyroid

Question 23

Mention 2 energy store in the form of protein

Answer 23

there’s no energy store in the form of protein

Question 24

Effect of thyroid hormone on nitrogen metabolism
-enhances only synthesis of proteins
T/F

Answer 24

F

Enhances both synthesis and degradation

Question 25

excess thyroid hormone promotes protein synthesis | T/F

Answer 25

F Degradation

Question 26

Effect of thyroid hormone on fat synthesis - glucose to _____ cycle - fatty acids are ____ constantly in ____ tissue - they become ______ or become ____ depending on ______ from _____ - requires optimal amounts of thyroid hormone

Answer 26

fatty acid produced adipose free fatty acids triglycerides glycerol phosphate glucose oxidation

Question 27

Thyroid and temperature regulation - ___ is the dominant form involved in it - exposure to cold causes ___ conversion to__ - promotes calorogenic effects (_______) - short term effects due to ______ effects and the _____ response of muscles

Answer 27

T3 Cold T4; T3 long term cold adaptation sympathetic mimetic shivering

Question 28

EFFECTS OF TSH - greatly ___eases endogenous synthesis and secretion of hormone - ___eases blood flow - ____ effect on Glandular Tissue, RNA AND DNA synthesis(Hyperplasia), phospholipid metabolism , ETC.  

Answer 28

incr incr pleiotropic

Question 29

ABNORMALITIES OF THYROID FUNCTION Hypo secretion - _____ bmr - ____ tolerance of Cold - ____ of Weight - Fatigue - ___ and ____ Pulse - ____ reflexes And mentation - myxedema - goiter - cretinism

Answer 29

reduced poor gain slow and Weak slow

Question 30

hyper secretion * _____ DISEASE: - EXOPHTALMOS - GOITER

Answer 30

grave’s

Question 31

TSI stands for ??

Answer 31

THYROID STIMULATING IMMUNOGLOBULIN

Question 32

In grave’s diseases ,___ MIMICS TSH

Answer 32

TSI

Question 33

The structures of T3 and T4 differ only by ______

Answer 33

a single atom of iodine

Question 34

almost all hormonal output of the thyroid gland is T_

Answer 34

4

Question 35

Thyroglobulin (TG), a glycoprotein containing large quantities of ______, is synthesized on the ____ and ______ of the thyroid follicular cells. TG is then incorporated into secretory vesicles and extruded across the ____ membrane into the ______. Later, the tyrosine residues of TG will be ____ to form the precursors of thyroid hormones.

Answer 35

tyrosine rough endoplasmic reticulum and the Golgi apparatus apical; follicular lumen iodinated

Question 36

In thyroid hormone synthesis Iodine is (passively or actively ?) transported from blood into the follicular epithelial cells against both chemical and electrical gradients.

Answer 36

Actively

Question 37

In thyroid hormone synthesis low levels of I− (inhibits or stimulate?) the iodine pump. Why???

Answer 37

Stimulate When there is a dietary deficiency of I−, the Na+-I− cotransport increases its activity, attempting to compensate for the deficiency.

Question 38

In thyroid hormone synthesis (competitive or non-competitive ?) inhibitors of Na+-I− cotransport includes the anions _______ and ______ , which block I− uptake into follicular

Answer 38

Competitive

Question 39

In thyroid hormone synthesis I− is oxidized to I2 by the enzyme thyroid _____.

Answer 39

peroxidase

Question 40

In thyroid hormone synthesis organification of I2 into TG is catalyzed by _____

Answer 40

Thyroid peroxidase

Question 41

Thyroid peroxidase is inhibited by ______ (__), which blocks the synthesis of thyroid hormones by blocking all of the steps catalyzed by thyroid peroxidase. Thus administration of PTU is an effective treatment for _____

Answer 41

propylthiouracil PTU hyperthyroidism.

Question 42

In thyroid hormone synthesis At the ___ membrane, just inside the lumen of the follicle, I2 combines with the tyrosine moieties of TG, catalyzed by _____, to form ——— and ———

Answer 42

apical thyroid peroxidase monoiodotyrosine (MIT) diiodotyrosine (DIT).

Question 43

MIT and DIT remain attached to TG in the follicular lumen until the thyroid gland is stimulated to secrete its hormones. T/F

Answer 43

T

Question 44

High levels of I− (inhibit or stimulate?) organification and synthesis of thyroid hormones

Answer 44

Inhibit

Question 45

Effect of high levels of iodine in thyroid hormone organification is known as the ______ effect

Answer 45

Wolff-Chaikoff effect.

Question 46

two molecules of DIT combine to form _____ . one molecule of DIT combines with one molecule of MIT to form _____.

Answer 46

T4 T3

Question 47

Which is faster?? Coupling reaction to get T4 or to get T3

Answer 47

T4

Question 48

All MIT and DIT undergoe the coupling reaction to form T3 and T4 T/F

Answer 48

F

Question 49

Hydrolysis of T4 and T3 from TG by ____ enzymes like _____

Answer 49

lysosomal Proteases

Question 50

MIT and DIT are also hydrolyzed from the TG complex in follicular cells T/F

Answer 50

T

Question 51

MIT and DIT also leave the follicular cells with T3 and T4 | T/F

Answer 51

F

Question 52

Finally , in thyroid hormone synthesis MIT and DIT are _____ inside the follicular cell by the enzyme thyroid _____

Answer 52

deiodinated deiodinase.

Question 53

A deficiency of thyroid deiodinase therefore mimics ______

Answer 53

dietary I− deficiency.