Thyroid Gland

Question 1

Which Deiodinase converts T4 to active T3?

Answer 1

Types 1 and 2

Question 2

Which Deiodinase converts T4 to inactive T3?

Answer 2

Type 3

Question 3

What factors will increase the conversion of T4 to T3?

Answer 3

Obesity

Cold exposure

Hyperthyroid

Question 4

What factors will decrease the conversion of T4 to T3?

Answer 4

1) pregnancy
2) Fasting
3) Beta-blockers
4) hepatic and renal failure
5) aging
6) hypothyroid

Question 5

What blocks the Na/I- symporter (NIS)

Answer 5

Perchlorate

Thiocynate

Question 6

What is the name of the transporter that brings I- from the follicular epithelial cell into the follicular lumen?

Answer 6

Pendrin

Question 7

What does Pendrin dependent on?

Answer 7

Chloride

Question 8

What enzyme in the follicular lumen puts and MIT and DIT on to TG and ultimately T4 and T3?

Answer 8

Peroxidase

Question 9

2 DIT molecules make what?

Answer 9

T4

Question 10

A DIT and an MIT molecule makes what?

Answer 10

T3

Question 11

Once pinocytosis occurs of the TG-thyroid hormone complex, what cleaves the thyroid hormones from the TG?

Answer 11

Proteases in the lysosomes

Question 12

Explain the Wolff-Chaikoff effect

Answer 12

High levels of I- inhibit organification cation and synthesis of thyroid hormones

Question 13

When TSH binds to a thyroid cell what is the secondary messenger system?

Answer 13

CAMP

Question 14

What are the 2 effects of TSH on a thyroid follicular cell?

Answer 14

1) increase synthesis and secretion of thyroid hormone

2) trophic effect on thyroid gland

Question 15

In most tissues, thyroid hormones stimulate synthesis of what?

Answer 15

Na/K ATPase

Question 16

In cardiac muscle cells, thyroid hormones stimulates the synthesis of what?

Answer 16

1) myosin
2) B1 adrenergic receptors
3) Ca+ ATPase

Question 17

what enzyme converts T4 to T3?

Answer 17

Deiodinase