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Bch 204 > Thyroid 1 > Flashcards

Thyroid 1 Flashcards

1
Q

Thyroid hormones SYNTHESIS
-dependent on iodine
T/F

A

T

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2
Q

Thyroid hormones SYNTHESIS

DEPENDENT ON TYROSINE
T/F

A

T

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3
Q

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

A

extra

luminal

FOLLICULAR LUMEN

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4
Q

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

A

T

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5
Q

Effects of Iodine

excess iodine inhibits synthesis

T/F

A

T

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6
Q

Thyroid hormone secretions

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

A

TSH

endocytosis

thyroglobulin

follicular cells

T3 and T4

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7
Q

Thyroid hormone binding

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

99

binding globulin

binding prealbumin; transthyretin

albumin

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8
Q

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

A

three

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9
Q

T4 binds better than T3

T/F

A

T

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10
Q

Thyroid hormones effects

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

incr

incr

incr

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11
Q

Thyroid hormone is parasympathomimetic

T/F

A

F

sympathomimetic

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12
Q

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

T/F

A

T

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13
Q

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

A

growth

Insulin-like growth

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14
Q

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

A

F

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15
Q

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

A

tolerance to cold

ATP

incr

genesis

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16
Q

THYROID HORMONES CONTROL FUEL METABOLISM

GLYCOGENESIS

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

branched

glucose

muscle

liver

insulin

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17
Q

Glycogenesis synthesis is by a seperate pathway from glycogenolysis

T/F

A

T

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18
Q

GLYCOGENOLYSIS

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

glucose

glucagon, epinephrine, norepinephrine, and glucocorticoids

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19
Q

Glycogenolysis regulates blood glucose between meals

T/F

A

T

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20
Q

Glycogenolysis is suppressed by thyroid hormone

T/F

A

F

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21
Q

GLUCONEOGENESIS

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

3 and 4

fructose phosphate

glucagon

thyroid

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22
Q

PROTEIN DEGRADATION

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

protein synthesis

glucagon

thyroid

23
Q

Mention 2 energy store in the form of protein

A

there’s no energy store in the form of protein

24
Q

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

A

F

Enhances both synthesis and degradation

25
Q

excess thyroid hormone promotes protein synthesis

T/F

A

F

Degradation

26
Q

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
A

fatty acid

produced

adipose

free fatty acids

triglycerides

glycerol phosphate

glucose oxidation

27
Q

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
A

T3

Cold

T4; T3

long term cold adaptation

sympathetic mimetic

shivering

28
Q

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.
A

incr

incr

pleiotropic

29
Q

ABNORMALITIES OF THYROID FUNCTION

Hypo secretion

  • _____ bmr
  • ____ tolerance of Cold
  • ____ of Weight
  • Fatigue
  • ___ and ____ Pulse
  • ____ reflexes And mentation
  • myxedema
  • goiter
  • cretinism
A

reduced

poor

gain

slow and Weak

slow

30
Q

hyper secretion

  • _____ DISEASE:
  • EXOPHTALMOS
  • GOITER
A

grave’s

31
Q

TSI stands for ??

A

THYROID STIMULATING IMMUNOGLOBULIN

32
Q

In grave’s diseases ,___ MIMICS TSH

A

TSI

33
Q

The structures of T3 and T4 differ only by ______

A

a single atom of iodine

34
Q

almost all hormonal output of the thyroid gland is T_

A

4

35
Q

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.

A

tyrosine

rough endoplasmic reticulum and the Golgi apparatus

apical; follicular lumen

iodinated

36
Q

In thyroid hormone synthesis

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

A

Actively

37
Q

In thyroid hormone synthesis

low levels of I− (inhibits or stimulate?) the iodine pump.

Why???

A

Stimulate

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

38
Q

In thyroid hormone synthesis

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

A

Competitive

39
Q

In thyroid hormone synthesis

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

A

peroxidase

40
Q

In thyroid hormone synthesis

organification of I2 into TG is catalyzed by _____

A

Thyroid peroxidase

41
Q

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 _____

A

propylthiouracil

PTU

hyperthyroidism.

42
Q

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 ———

A

apical

thyroid peroxidase

monoiodotyrosine (MIT)

diiodotyrosine (DIT).

43
Q

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

T/F

A

T

44
Q

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

A

Inhibit

45
Q

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

A

Wolff-Chaikoff effect.

46
Q

two molecules of DIT combine to form _____ .

one molecule of DIT combines with one molecule of MIT to form _____.

A

T4

T3

47
Q

Which is faster??

Coupling reaction to get T4 or to get T3

A

T4

48
Q

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

T/F

A

F

49
Q

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

A

lysosomal

Proteases

50
Q

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

A

T

51
Q

MIT and DIT also leave the follicular cells with T3 and T4

T/F

A

F

52
Q

Finally , in thyroid hormone synthesis

MIT and DIT are _____ inside the follicular cell by the enzyme thyroid _____

A

deiodinated

deiodinase.

53
Q

A deficiency of thyroid deiodinase therefore mimics ______

A

dietary I− deficiency.

Bch 204 (14 decks)

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