Iodine

Question 1

Iodine exists naturally as what?

Answer 1

I2 as a gas

Question 2

What is Iodide?

Answer 2

The ionic form and is soluble in water

Question 3

What foods is generally found in?

Answer 3

Variety but found in milk because Iodine is used as a disinfectant for milking supplies

Question 4

Meat and vegetable content varies depending on?

Answer 4

Soil content of region where produced

Question 5

What areas of the world are low in iodine?

Answer 5

Mountanous areas

Question 6

What is the recommended vehicle for distributing iodine?

Answer 6

Salt

Question 7

How is Iodide absorbed into the intestinal cell?

Answer 7

Via a Na/I symporter

Question 8

What form of Iodide is used in fortification and why?

Answer 8

Iodate (IO3-) because it is highly bioavailable.

Question 9

Iodide is taken up rapidly by what?

Answer 9

Thyroid glands and kidneys

Question 10

When does the thyroid gland take up more or less Iodide?

Answer 10

More- in iodide def

Less- in adequate iodide intake

Question 11

Primary route of excretion?

Answer 11

Urinary

Question 12

Is there a mechanism to conserve iodide in the kidneys?

Answer 12

No

Question 13

Where is most of the iodide in the body?

Answer 13

In the thyroid glands

Question 14

What controls the concentration of blood iodide?

Answer 14

The thyroid gland only. not the intestinal tract not the kidney

Question 15

What is Iodide’s function?

Answer 15

Synthesis of thyroid hormones by the thyroid gland

Question 16

Which thyroid hormones are synthesized by Iodide?

Answer 16

Thyroxine (T4) and Triiodothyronine (T3)

Question 17

Slide 19

Answer 17

.

Question 18

T4 and T3 are associated with 3 transport proteins:

Answer 18

Thyroxine-binding protein

• Albumin
• transthyretin

Question 19

In order for T3 or T4 to be hormonally active it must be:

Answer 19

in the free form

Question 20

Slide 21.

Answer 20

.

Question 21

Deiodination of T4 can produce

Answer 21

T3 or rT3

Question 22

In order to deiondinate T4 what is needed?

Answer 22

5’-deiodinase

Question 23

Status assessment of Iodine

Answer 23

Urinary iodine excretion and functional indicators such as Thyroxine (T4) or serum thyroid stimulating hormone (TSH)

Question 24

What is the function of the thyroid hormones?

Answer 24

Regulator of prenatal cell growth

• influences neuronal health
• growth and maturation of peripheral tissues
• -deficiency causes delay in bone bone development

Question 25

Thyroid hormone deficiency

Answer 25

Basal metabolic rate (BMR) decreased Macronutrient metabolism impaired Developmental abnormalities in the bran, muscle/skeletal/lung

Question 26

Slide 27.

Answer 26

.

Question 27

Consequences of Iodine def?

Answer 27

``` Mental retardation Postnatally -delayed growth -slowness of movement -delayed reflexes -elevated blood lipids -cardiac insufficiency Goiter ```

Question 28

What is the most common consequence of iodine def that can be prevented?

Answer 28

mental retardation

Question 29

What is the compensatory response of Goiter?

Answer 29

``` Decrease Plasma iodide Hormone Synthesis Increase TSH release -Thyroid cell number increase -Thyroid cell size increase -Enlarged thyroid gland (goiter) ```

Question 30

If function is gained back during goiter, it may lead to what?

Answer 30

Thyroxicosis- overproduction of hormone

Question 31

What are symptomes of goiter?

Answer 31

Tracheal and esophagus pressure May damage laryngeal nerves respiratory difficulty hoarseness

Question 32

Your pituitary gland will sense what?

Answer 32

If your levels of T3 or T4 are low. If they are low, pituitary gland will make more TSH (thyroid stimulating hormone) to make more T3 or T4

Question 33

How do you treat goiters if caught early enough?

Answer 33

Gradual reduction of thyriod gland size with iodine supplement OR thyroidectomy

Question 34

What is the risk of having a thyroidectomy?

Answer 34

Patients may become hyperthyroid and require hormone replacement. Not practical in most affected places of the world.

Question 35

In pregnancy, what happens to iodine excretion and thyroid hormone secretion?

Answer 35

Iodine excretion increases and thyroid hormone secretion increases

Question 36

Decreased iodine during pregnancy may lead to?

Answer 36

Decreased thyroid hormone which leads to severe mental retardation and cretinism

Question 37

What is cretinism?

Answer 37

Most severe form of damage from iodide deficiency

Question 38

What is early pregnancy iodide deficiency?

Answer 38

Inner ear and brain affected mental retardation short stature but frewuently normal

Question 39

What is late pregnancy iodide deficiency?

Answer 39

``` Known as myxedematous shorter stature mental retardation hypothyroidism spasticity of legs, deaf mutism, goiter usually absent ```

Question 40

What are goitrogens?

Answer 40

Present in certain foods and blocks iodine uptake by thyroid (blocks Na/I symporter)

Question 41

Selenium Def can cause what?

Answer 41

Iodine Def

Question 42

How does Glutathione Peroxidase affect thyroid hormone synthesis?

Answer 42

It protects it from oxidative environment required for thyroid hormone synthesis.

Question 43

What does T4 deiodinase do?

Answer 43

Converts T4 to T3

Question 44

What happens to Iodine during selenium def?

Answer 44

Produces peroxidase deficiency in thyroid | deiododinase deficiency inhibits T3 production