Thyroid Hormones

Question 1

How many mg of iodine are required each year?

Answer 1

50

Question 2

Where is iodine absorbed?

Answer 2

from gut tract in same manner as chlorides

Question 3

What is the ratio for the sodium-iodine symporter?

Answer 3

2:1 in basal membane of thyroid

Question 4

Where does the engery for the sodium-iodine pump come from?

Answer 4

sodium-potassium ATPase pump

Question 5

How is iodide transported?

Answer 5

across apical membrane into follicle via chloride iodide counter-trasporter = pendrin

Question 6

KNOW IGURE 76.2 on IODINE TRANSPORT

Answer 6

look now plz look now`

Question 7

Where is thyroglobulin secreted?>

Answer 7

thyroid cells

Question 8

How many tyrosine amino acids are for each thyroglobulin?

Answer 8

70 which bind to iodine

Question 9

T/F Iodine ions can bind directly to tyrosine

Answer 9

T

Question 10

What is the major hormonal product in iodine metabolism?

Answer 10

thyroxine (T4) which can be converted to T3

Question 11

How is thyroxine formed?

Answer 11

two molecules of diiodotyrosine are joined

Question 12

How is triiodothyronine (T3) formed?

Answer 12

one monoiodotyrosine with one diiodotyrosine

Question 13

How many molecules of thyroxine are in a thyroglobulin?

Answer 13

30

Question 14

How are thyroid hormones released?

Answer 14

Form pinocytic vesicles
Fuse with lysosomes that break down thyroglobulin to release T3 and T4
Diffuse into blood
Most released as T4 but can be converted to T3
Most are immediately bound to plasma protein
Once bound released slowly into tissue

Question 15

What does most of the iodinated tyrosine in the thyroglobulin do?

Answer 15

recycled using deiodinase enzyme

Question 16

What are the physiological functions of thyroid hormones?

Answer 16

increaed transcription
increased cellular metabolic activity
Effects growth
Effects metablosm of carbs and fats
Increase BMR 
Decrease body weight
Increased GI
Excitatory on CNS
Trouble Sleepings
Effect sexual function

Question 17

What effect does TSH have on thyroid secretion?

Answer 17

increase release from thyroid

Question 18

What effect does cAMP have on thyroid secretion?

Answer 18

decrease thyroid releasing

Question 19

What effect does TRH have on thyroid secretion?

Answer 19

increase release of thyroid hormones

Question 20

What effect does cold have on thyroid secretion?

Answer 20

increase release of thyroid hormones

Question 21

What are the two causes of Hyperthyroidism

Answer 21

Grave’s Disease, Adenoma

Question 22

What are the symptoms of hyperthyroidism?

Answer 22

Excitability, intolerance to head, sweating, weight loss, diarrhea, muscle weakness, trouble seeing, hand tremors

Question 23

What is exophthalmos and when does it occur

Answer 23

eyes appear as they are bulging out because skin around it is retracting

occurs during hyperthyroidism

Question 24

What is the treatment for hyperthyroidism?

Answer 24

surgical removal of thyroid, or treat with radioactive iodine

Question 25

What are the causes of hypothyroidism?

Answer 25

Hashimoto disease (autoimmunity)
Endemic goiter
Cretinism

Question 26

What are the symptoms of hypothyroidism?

Answer 26

Opposite of hyperthyroidism
Myxedema
Atherosclerosis

Question 27

What is the treatment for hypothyroidism?

Answer 27

oral medication

Question 28

What are three types of antithyroid drugs?

Answer 28

Thiocyanate ions
Propylthiouracil
Iodides

Question 29

One of the best known stimuli for increasing the rate of thyroid releasing hormone is

Answer 29

cold

Question 30

Which of the following is a common cause of hyperthyroidism?

Answer 30

Grave’s Disease

Question 31

The basal membranes of thyroid cells contain symporters for iodine. What ion is cotransported with iodine by these symporters?

Answer 31

Sodium

Question 32

Down regulation of receptor may occur as a result of which of the following

Answer 32

Inactivation of some of the intracellular proton signaling molecules.